Brief analysis of jQuery's summary of select operations (traversing options, operating options)_jquery

//遍历option和添加、移除option
function changeShipMethod(shipping){
 var len = $("select[@name=ISHIPTYPE] option").length
 if(shipping.value != "CA"){
  $("select[@name=ISHIPTYPE] option").each(function(){
   if($(this).val() == 111){
    $(this).remove();
   }
  });
 }else{
  $("UPS Ground").appendTo($("select[@name=ISHIPTYPE]"));
 }
}
//取得下拉选单的选取值
$('#testSelect option:selected').text();
或$("#testSelect").find('option:selected').text();
或$("#testSelect").val();
//////////////////////////////////////////////////////////////////
记性不好的可以收藏下：
1,下拉框:
var cc1   = $(".formc select[@name='country'] option[@selected]").text(); //得到下拉菜单的选中项的文本(注意中间有空格)
var cc2 = $('.formc select[@name="country"]').val();   //得到下拉菜单的选中项的值
var cc3 = $('.formc select[@name="country"]').attr("id"); //得到下拉菜单的选中项的ID属性值
$("#select").empty();//清空下拉框//$("#select").html('');
$("1111").appendTo("#select")//添加下拉框的option

稍微解释一下:
1.select[@name='country'] option[@selected] 表示具有name 属性，
并且该属性值为'country' 的select元素 里面的具有selected 属性的option 元素；
可以看出有@开头的就表示后面跟的是属性。

2,单选框:
$("input[@type=radio][@checked]").val();   //得到单选框的选中项的值(注意中间没有空格)
$("input[@type=radio][@value=2]").attr("checked",'checked'); //设置单选框value=2的为选中状态.(注意中间没有空格)

3,复选框:
$("input[@type=checkbox][@checked]").val(); //得到复选框的选中的第一项的值
$("input[@type=checkbox][@checked]").each(function(){ //由于复选框一般选中的是多个,所以可以循环输出
   alert($(this).val());
   });

$("#chk1").attr("checked",'');//不打勾
$("#chk2").attr("checked",true);//打勾
if($("#chk1").attr('checked')==undefined){} //判断是否已经打勾
当然jquery的选择器是强大的. 还有很多方法.

aaass


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jquery radio value, checkbox value, select value, radio selected, checkbox selected, select selected, and related to obtain a group of radios selected The value of the item
var item = $('input[@name=items][@checked]').val();
Get the text of the selected item in select
var item = $("select [@name=items] option[@selected]").text();
The second element of the select drop-down box is the currently selected value
$('#select_id')[0].selectedIndex = 1 ;
The second element of the radio radio selection group is the currently selected value
$('input[@name=items]').get(1).checked = true;
Get value:
Text box, text area: $("#txt").attr("value");
Multiple selection box checkbox: $( "#checkbox_id").attr("value");
Radio group radio: $("input[@type=radio][@checked]").val();
Drop-down box select: $('#sel').val();
Control form element:
Text box, text area: $("#txt").attr("value",'');//Clear the content
                                                      🎜>
Multiple selection box checkbox: $("#chk1").attr("checked",'');//Unchecked    $("#chk2").attr(" checked",true); // Check
if($("#chk1").attr('checked')==undefined) // Determine whether it has been checked

Radio group radio ： $("input[@type=radio]").attr("checked",'2');//Set the item with value=2 as the currently selected item
drop-down box select: $("#sel").attr("value",'-sel3');//Set the item with value=-sel3 as the currently selected item                                                                                       ;1111 2222").appendTo("#sel")//Add the option
of the drop-down box    $("#sel").empty( ); //Clear the drop-down box

Get the value of a set of radio selected items

var item = $('input[@name=items][@checked]').val();
Get the text of the selected item
var item = $("select[@name=items] option[@selected]").text();
The second element of the select drop-down box is the currently selected value
$('#select_id ')[0].selectedIndex = 1;
The second element of the radio radio selection group is the currently selected value
$('input[@name=items]').get(1).checked = true ;

Get value:
text box, text area: $("#txt").attr("value");
many Checkbox: $("#checkbox_id").attr("value");
Radio group radio: $("input[@type=radio][@checked] ").val();
Drop-down box select: $('#sel').val();
Control form element:
Text box, text area: $("#txt").attr("value",'');//Clear the content$("#txt").attr("value",' 11');//Fill content

Multiple selection box checkbox: $("#chk1").attr("checked",'');//Unchecked$( "#chk2").attr("checked",true);//Check
if($("#chk1").attr('checked')==undefined) //Determine whether it has been checked

Radio group radio: $("input[@type=radio]").attr("checked",'2');//Set the item with value=2 as the currently selected item
Drop-down box select: $("#sel").attr("value",'-sel3');//Set the item with value=-sel3 as the currently selected item$( "11112222").appendTo("#sel")//Add the option of the drop-down box
$("#sel").empty();//Clear the drop-down box