Table of Contents
HTML ------ 关于表单 Form - Tina_xy
Form(表单)主要用于采集和提交用户输入的信息，是页面与WEB服务器交互过程中 最重要的信息来源。
掌握表单(Form)有以下几个要点：
重要form属性
form常用控件
form提交方式
§ 重要form属性
action {URL}：规定表单提交时向何处发送数据。
enctype ：规定在发送表单数据之前如何对表单数据进行编码。（值如下）
application/x-www-form-urlencoded ：在发送前编码所有字符（默认为此方式）。
multipart/form-data ：不对字符编码。 注：使用包含文件上传控件的表单时，必须使用该值。
method：指定表单以何种方法发送。
get ：from表单里所填的值，附加在action指定的URL后面，做为URL链接而传递。（可以在地址栏看见表单的提交信息）
post ：from表单里所填的值，附加在HTML Headers上。（不可以在地址栏看见表单的提交信息）
§ form常用控件
建议：每一个表单元素的文字描述都使用（两标签之间的内容即为对绑定的表单控件的文字描述）
注意：每个表单元素应当分配 name 属性 和 id 属性。( name 属性和 id 属性应该尽可能地使用相同的或相关的值。)
name 属性：用来将数据提交到服务器；
id 属性：用来在客户端做相应的操作；如：
文本输入框:
1)、input type="text" 单行文本框
<span style="font-size: 15px;"><span style="color: #0000ff;"><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">= "Account"</span><span style="color: #0000ff;">></span>账号：<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="text"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="Account"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="Account"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="账户" maxlength="20"</span><span style="color: #0000ff;">></span></span></span></span>
Copy after login
2)、textarea 多行文本框
<span style="font-size: 15px;"><span style="color: #0000ff;"><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">="comment"</span><span style="color: #0000ff;">></span>评论：<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">textarea </span><span style="color: #ff0000;">name</span><span style="color: #0000ff;">="comment"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="comment"</span><span style="color: #ff0000;"> cols</span><span style="color: #0000ff;">="30"</span><span style="color: #ff0000;"> rows</span><span style="color: #0000ff;">="15" maxlength="100"</span><span style="color: #0000ff;">></span><span style="color: #800000;">textarea</span><span style="color: #0000ff;">></span></span></span></span>
Copy after login
说明: maxlength 规定文本区域的最大字符数；如果在
密码输入框：
定义密码字段。（字符会被遮盖）
<span style="font-size: 15px;"><span style="color: #0000ff;"><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">= "Password"</span><span style="color: #0000ff;">></span>密码：<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span> <span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="password"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="password"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="password"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="密码"</span><span style="color: #0000ff;">></span></span></span></span>
Copy after login
单选框：
设置单选按钮 以及获取选中的单选按钮的值
<span style="font-size: 15px;"><span style="color: #0000ff;"><span style="color: #800000;">form </span><span style="color: #ff0000;">name</span><span style="color: #0000ff;">="MyForm"</span><span style="color: #ff0000;"> action</span><span style="color: #0000ff;">="URL"</span><span style="color: #ff0000;"> method</span><span style="color: #0000ff;">="post"</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span><span style="color: #000000;">性别：
</span><span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="radio"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="sex"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="male"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="male"</span><span style="color: #0000ff;">><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">="male"</span><span style="color: #0000ff;">></span>male<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="radio"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="sex"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="female"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="female"</span><span style="color: #0000ff;">><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">="female"</span><span style="color: #0000ff;">></span>female<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="button"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="获取选中项"</span><span style="color: #ff0000;"> onclick</span><span style="color: #0000ff;">="getValue();"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">form</span><span style="color: #0000ff;">><br><br></span><span style="color: #000000;">//获取选中的单选值
</span><span style="color: #0000ff;"><span style="color: #800000;">script </span><span style="color: #ff0000;">language</span><span style="color: #0000ff;">="javascript"</span><span style="color: #0000ff;">></span>
<span style="background-color: #f5f5f5; color: #0000ff;">function</span><span style="background-color: #f5f5f5; color: #000000;"> getValue(){
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">获取表单的所有提交信息（根据表单的name属性）</span>
<span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> myform </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> document.forms[</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">MyForm</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">];
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">sex是单选按钮的name属性值</span>
<span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> radioChoices </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> myform.sex;
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">遍历整个单选项表</span>
<span style="background-color: #f5f5f5; color: #0000ff;">for</span><span style="background-color: #f5f5f5; color: #000000;">(i</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">;i</span><span style="background-color: #f5f5f5; color: #000000;"><span style="background-color: #f5f5f5; color: #000000;">radioChoices.length;i</span><span style="background-color: #f5f5f5; color: #000000;">++</span><span style="background-color: #f5f5f5; color: #000000;">)
</span><span style="background-color: #f5f5f5; color: #0000ff;">if</span><span style="background-color: #f5f5f5; color: #000000;">(radioChoices[i].checked)
</span><span style="background-color: #f5f5f5; color: #0000ff;">break</span><span style="background-color: #f5f5f5; color: #000000;">; </span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">发现了被选中项,退出</span>
<span style="background-color: #f5f5f5; color: #000000;"> alert(</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">选中的选项是：</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">+</span><span style="background-color: #f5f5f5; color: #000000;">radioChoices[i].value);
}
</span><span style="color: #0000ff;"></span><span style="color: #800000;">script</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span>Copy after login
注意：
1）、在客户端，Javascript 对表单及表单元素的操作，更常用其name 属性而不是id属性。因为，对于某些特定的表单元素(如：单选按钮等)，使用其name 属性更易于获得元素值，也更方便向服务器传送数据！
2）、保证同一组单选按钮的name 属性值相同。
复选框：
复选框的“全选”、“全不选”、“反选”功能 以及 所选复选框值的获得功能
<span style="font-size: 15px;"><span style="color: #0000ff;"><span style="color: #800000;">form </span><span style="color: #ff0000;">name</span><span style="color: #0000ff;">="MyForm"</span><span style="color: #ff0000;"> action</span><span style="color: #0000ff;">="URL"</span><span style="color: #ff0000;"> method</span><span style="color: #0000ff;">="post"</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="checkbox"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="hoboy"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="music"</span><span style="color: #0000ff;">><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">="music"</span><span style="color: #0000ff;">></span>music<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="checkbox"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="hoboy"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="swim"</span><span style="color: #0000ff;">><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">="swim"</span><span style="color: #0000ff;">></span>swim<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"> <span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="checkbox"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="hoboy"</span><span style="color: #ff0000;"> id</span><span style="color: #0000ff;">="dance"</span><span style="color: #0000ff;">><span style="color: #800000;">label </span><span style="color: #ff0000;">for</span><span style="color: #0000ff;">="dance"</span><span style="color: #0000ff;">></span>dance<span style="color: #0000ff;"></span><span style="color: #800000;">label</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="button"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="全选"</span><span style="color: #ff0000;"> onclick</span><span style="color: #0000ff;">="selectBoxs(1);"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="button"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="全不选"</span><span style="color: #ff0000;"> onclick</span><span style="color: #0000ff;">="selectBoxs(0);"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="button"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="反选"</span><span style="color: #ff0000;"> onclick</span><span style="color: #0000ff;">="selectBoxs(-1);"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="submit"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="提交"</span><span style="color: #ff0000;"> onclick</span><span style="color: #0000ff;">="submit();"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">form</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">script </span><span style="color: #ff0000;">language</span><span style="color: #0000ff;">="javascript"</span><span style="color: #0000ff;">></span>
<span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">全选，全部选，反选</span>
<span style="background-color: #f5f5f5; color: #0000ff;">function</span><span style="background-color: #f5f5f5; color: #000000;"> selectBoxs(value){
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> myform </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> document.forms[</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">MyForm</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">];
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">hoboy 为所有复选框的name属性值</span>
<span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> CheckboxChoices </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> myform.hoboy;
</span><span style="background-color: #f5f5f5; color: #0000ff;">for</span><span style="background-color: #f5f5f5; color: #000000;">(</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> i</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">;i</span><span style="background-color: #f5f5f5; color: #000000;"><span style="background-color: #f5f5f5; color: #000000;">CheckboxChoices.length;i</span><span style="background-color: #f5f5f5; color: #000000;">++</span><span style="background-color: #f5f5f5; color: #000000;">) </span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">遍历每一个选项</span>
<span style="background-color: #f5f5f5; color: #0000ff;">if</span><span style="background-color: #f5f5f5; color: #000000;">(value </span><span style="background-color: #f5f5f5; color: #000000;"> <span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">)</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">反选</span>
<span style="background-color: #f5f5f5; color: #000000;"> CheckboxChoices[i].checked </span><span style="background-color: #f5f5f5; color: #000000;">=</span> <span style="background-color: #f5f5f5; color: #000000;">!</span><span style="background-color: #f5f5f5; color: #000000;">CheckboxChoices[i].checked;
</span><span style="background-color: #f5f5f5; color: #0000ff;">else</span>
<span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">value为1是则全选,为0时则全不选</span>
<span style="background-color: #f5f5f5; color: #000000;"> CheckboxChoices[i].checked </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> value;
}
</span><span style="background-color: #f5f5f5; color: #0000ff;">function</span><span style="background-color: #f5f5f5; color: #000000;"> getSelect(){
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> myform </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> document.forms[</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">MyForm</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">];
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> CheckboxChoices </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> myform.hoboy;
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">创建数组放checkbox选中的值</span>
<span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> arrayCheckbox </span><span style="background-color: #f5f5f5; color: #000000;">=</span> <span style="background-color: #f5f5f5; color: #0000ff;">new</span><span style="background-color: #f5f5f5; color: #000000;"> Array();
</span><span style="background-color: #f5f5f5; color: #0000ff;">for</span><span style="background-color: #f5f5f5; color: #000000;">(</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> i</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">;i</span><span style="background-color: #f5f5f5; color: #000000;"><span style="background-color: #f5f5f5; color: #000000;">CheckboxChoices.length;i</span><span style="background-color: #f5f5f5; color: #000000;">++</span><span style="background-color: #f5f5f5; color: #000000;">){
</span><span style="background-color: #f5f5f5; color: #0000ff;">if</span><span style="background-color: #f5f5f5; color: #000000;">(CheckboxChoices[i].checked)
arrayCheckbox.push(CheckboxChoices[i].value);
}
alert(arrayCheckbox);
}
</span><span style="color: #0000ff;"></span><span style="color: #800000;">script</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>Copy after login
注意：保证同一组复选框按钮的name 属性值相同。
下拉框：
下拉框的重要属性：
multiple 属性:用于设置下拉表框的类型（多选还是单选）
type 属性：JS根据type 属性的值获得下拉列表框select 控件的类型。
type 属性的值为：select-multiple（多选） 或 select-one（单选）
下拉列表框默认只能选中一项，若要设置为可以多选，则设置
size属性：定义可见选项的数目。size="3",即下拉框内可以显示三个可选选项。
<span style="font-size: 15px;"><span style="color: #0000ff;"><span style="color: #800000;">form </span><span style="color: #ff0000;">name</span><span style="color: #0000ff;">="MyForm"</span><span style="color: #ff0000;"> action</span><span style="color: #0000ff;">="URL"</span><span style="color: #ff0000;"> method</span><span style="color: #0000ff;">="post"</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>简单的选择列表<span style="color: #0000ff;"></span><span style="color: #800000;">p</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">select </span><span style="color: #ff0000;">id</span><span style="color: #0000ff;">="myselect"</span><span style="color: #ff0000;"> name</span><span style="color: #0000ff;">="myselect"</span><span style="color: #ff0000;"> multiple</span><span style="color: #0000ff;">="multiple"</span><span style="color: #ff0000;"> size</span><span style="color: #0000ff;">="3"</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">option </span><span style="color: #ff0000;">value</span><span style="color: #0000ff;">="Apples"</span><span style="color: #0000ff;">></span>Apples<span style="color: #0000ff;"></span><span style="color: #800000;">option</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">option </span><span style="color: #ff0000;">value</span><span style="color: #0000ff;">="Bananas"</span><span style="color: #0000ff;">></span>Bananas<span style="color: #0000ff;"></span><span style="color: #800000;">option</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">option </span><span style="color: #ff0000;">value</span><span style="color: #0000ff;">="Cherries"</span><span style="color: #0000ff;">></span>Cherries<span style="color: #0000ff;"></span><span style="color: #800000;">option</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">option </span><span style="color: #ff0000;">value</span><span style="color: #0000ff;">="oranges"</span><span style="color: #0000ff;">></span>oranges<span style="color: #0000ff;"></span><span style="color: #800000;">option</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">select</span><span style="color: #0000ff;">></span><span style="color: #800000;">br</span><span style="color: #0000ff;">></span>
<span style="color: #0000ff;"><span style="color: #800000;">input </span><span style="color: #ff0000;">type</span><span style="color: #0000ff;">="button"</span><span style="color: #ff0000;"> onclick</span><span style="color: #0000ff;">="getSelectValue('myselect')"</span><span style="color: #ff0000;"> value</span><span style="color: #0000ff;">="查看选项"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">form</span><span style="color: #0000ff;">><br><br></span><span style="color: #0000ff;"><span style="color: #800000;">script </span><span style="color: #ff0000;">language</span><span style="color: #0000ff;">="javascript"</span><span style="color: #0000ff;">></span>
<span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">获取选中的下拉列表值</span>
<span style="background-color: #f5f5f5; color: #0000ff;">function</span><span style="background-color: #f5f5f5; color: #000000;"> getSelectValue(myselect){
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> myform </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> document.forms[</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">MyForm</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">];
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> select </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> myform.elements[myselect];
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">判断是单选还是多选</span>
<span style="background-color: #f5f5f5; color: #0000ff;">if</span><span style="background-color: #f5f5f5; color: #000000;">(select.type </span><span style="background-color: #f5f5f5; color: #000000;">==</span> <span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">selece-one</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">){
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> oneChoice </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> select.selectedIndex;</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">获取选中项</span>
<span style="background-color: #f5f5f5; color: #000000;"> alert(</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">单选</span><span style="background-color: #f5f5f5; color: #000000;">"</span> <span style="background-color: #f5f5f5; color: #000000;">+</span><span style="background-color: #f5f5f5; color: #000000;"> select.options[oneChoice].value);</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">获取选中项的值</span>
<span style="background-color: #f5f5f5; color: #000000;"> }
</span><span style="background-color: #f5f5f5; color: #0000ff;">else</span><span style="background-color: #f5f5f5; color: #000000;">{
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> multiChoices </span><span style="background-color: #f5f5f5; color: #000000;">=</span> <span style="background-color: #f5f5f5; color: #0000ff;">new</span><span style="background-color: #f5f5f5; color: #000000;"> Array();
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">遍历整个下拉菜单</span>
<span style="background-color: #f5f5f5; color: #0000ff;">for</span><span style="background-color: #f5f5f5; color: #000000;">(</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> i</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">;i</span><span style="background-color: #f5f5f5; color: #000000;"><span style="background-color: #f5f5f5; color: #000000;">select.options.length;i</span><span style="background-color: #f5f5f5; color: #000000;">++</span><span style="background-color: #f5f5f5; color: #000000;">)
</span><span style="background-color: #f5f5f5; color: #0000ff;">if</span><span style="background-color: #f5f5f5; color: #000000;">(select.options[i].selected)</span>
<span style="background-color: #f5f5f5; color: #000000;"> multiChoices.push(select.options[i].value);</span>
<span style="background-color: #f5f5f5; color: #000000;"> alert(</span><span style="background-color: #f5f5f5; color: #000000;">"</span><span style="background-color: #f5f5f5; color: #000000;">多选</span><span style="background-color: #f5f5f5; color: #000000;">"</span> <span style="background-color: #f5f5f5; color: #000000;">+</span><span style="background-color: #f5f5f5; color: #000000;"> multiChoices);
}
}
</span><span style="color: #0000ff;"></span><span style="color: #800000;">script</span><span style="color: #0000ff;">></span></span></span></span></span></span></span></span></span></span></span></span>Copy after login
提示：
在不同操作系统中，选择多个选项的差异：
- 对于 windows：按住 Ctrl 按钮来选择多个选项
- 对于 Mac：按住 command 按钮来选择多个选项
由于上述差异的存在，同时由于需要告知用户可以使用多项选择，对用户更友好的方式是使用复选框。
§ form提交方式
表单的提交方式由method属性的取值决定，所以form提交方式有以下两种：
get 方式：
表单数据将会追加action指定的URL后面，做为URL链接而传递（以查询字符串的形式提交到服务端）。
变量提交的样式为：html元素的name属性=提交的值。多个变量，在URL链接后面以 & 符号隔开。
post方式：
表单数据将附加在请求体（HTML Headers）上被发送出去，并不附加在URL链接后面。
建议：表单通常还是以post方式提交比较好，这样可以不破坏URL，况且URL还有长度限制。
get 与 post 的区别：
1）、get是从服务器上获取数据；post是向服务器传送数据
2）、数据的查询：比如浏览论坛或博客时，URL一般包含了分类、页码数、每页记录数等信息。 get 方式，能一目了然的看到所要查询的信息； post 因为隐藏掉了这些信息，不方便进行查询。
3）、数据安全性：对一项记录，进行更改、添加操作时，get 方式附加在URL上，会泄露数据；post 方式，能隐藏数据，保证数据的安全性。
4）、数据传输量：get 虽然方便查询，但由于是附加在URL上，使得其传送的数据量较小，不能大于2KB；post传送的数据量较大，一般被默认为不受限制。
资源链接
推荐 ：更多代码详解，请转到代码仓库：https://github.com/Tina-xy/HTML
推荐 ： Fish Li 博主的 ---- 细说Form(表单)
http://www.cnblogs.com/fish-li/archive/2011/07/17/2108884.html
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