js form validation example explanation_javascript skills-JS Tutorial-php.cn

js form validation example explanation_javascript skills

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Release： 2016-05-16 15:07:16

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The example in this article shares js form verification for everyone’s reference. The specific content is as follows

JavaScript can be used to validate input data in HTML forms before the data is sent to the server.
Typical form data validated by JavaScript are:
1). Has the user filled in the required items in the form?
2) Is the email address entered by the user legal?
3) Has the user entered a legal date?
4) Has the user entered text in the numeric field?

gspan.html

<html>
<head>
  <title>表单验证实例</title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <script src="check.js" type="text/javascript"></script>
  <style>
    span{ font-size:12px; }
    .stats1{ color : #ccc; }
    .stats2{ color :black; }
    .stats3{ color :red; }
    .stats4{ color :green; }
 
  </style>
</head>
<body>
  <form method="post" action="reg.php" onsubmit="return regs('click')" >
    用户名：<input type="text" name="username" /><span class="stats1">用户名不能为空</span><br/>
    邮箱：<input type="text" name="email" /><span class="stats1">邮箱不能为空</span><br/>
    密码：<input type="password" name="password" /><span class="stats1">密码不能为空</span><br/>
    确认密码：<input type="password" name="chkpass" /><span class="stats1">密码不能为空</span><br/>
    <input type="submit" />
  </form>
</body>
</html>

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check.js

function gspan(cobj){    //获取表单后的span 标签 显示提示信息
  if (cobj.nextSibling.nodeName != 'SPAN'){
    gspan(cobj.nextSibling);
  } else {
    return cobj.nextSibling;
  }
}
 
//检查表单 obj【表单对象】， info【提示信息】 fun【处理函数】 click 【是否需要单击， 提交时候需要触发】
function check(obj, info, fun, click){
  var sp = gspan(obj);
  obj.onfocus = function(){
    sp.innerHTML = info;
    sp.className = 'stats2';
  }
 
  obj.onblur = function(){
    if (fun(this.value)){
      sp.innerHTML = "输入正确！";
      sp.className = "stats4";
    } else {
      sp.innerHTML = info;
      sp.className = "stats3";
    }
  }
 
  if (click == 'click'){
    obj.onblur();
  }
}
 
onload = regs;   //页面载入完执行
 
function regs(click){
  var stat = true;    //返回状态， 提交数据时用到
  username = document.getElementsByName('username')[0];
  password = document.getElementsByName('password')[0];
  chkpass = document.getElementsByName('chkpass')[0];
  email = document.getElementsByName('email')[0];
   
  check(username, "用户名的长度在3-20之间", function(val){
    if (val.match(/^\S+$/) && val.length >=3 && val.length <=20){
      return true;
    } else {
      stat = false;
      return false;
    }
  }, click);
 
  check(password, "密码必须在6-20位之间", function(val){
    if (val.match(/^\S+$/) && val.length >= 6 && val.length <=20){
      return true;
    } else {
      stat = false;
      return false;
    }
  }, click);
 
   
  check(chkpass, "确定密码要和上面一致，规则也要相同", function(val){
    if (val.match(/^\S+$/) && val.length >=6 && val.length <=20 && val == password.value){
      return true;
    } else {
      stat = false;
      return false;
    }
  }, click);
 
  check(email, "请按邮箱规则输入", function(val){
    if (val.match(/\w+@\w+\.\w/)){
      return true;
    } else {
      stat = false;
      return false;
    }
  }, click);
  return stat;
}

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