javascriptの使用(6)formvalidフォームの検証

1575 ワード

JavaScript フォームの検証 formvalid

<html>
 <head>
  <title>    </title>
  <script type="text/javascript">
    function valid(){
  var username=document.getElementById("username");
  if(username.value==""){
        alert("      ");
return;
  }
  if(username.value.length<6){
 alert("        6   ");
     return;
  }
      var email=document.getElementById("email");
      var atIndex=email.value.indexOf("@");
      var dotIndex=email.value.indexOf(".");
      if(atIndex==-1 || dotIndex==-1){
    alert("    @ .  ");
return;
  }
      if(atIndex>dotIndex){
  alert("@     .  ");
  return;
  }
      if(dotIndex-atIndex==1){
          alert("@ .    ");
  return;
  }
      var registerForm=document.getElementById("registerForm");
  //    
      registerForm.submit();
}
  </script>
 </head>
 <body>
 <form id="registerForm" action="http://www.baidu.com" method="post" >
      ：<input type="text" name="username" id="username" />
   <br/>
     :<input type="password" name="password" id="password" />
   <br/>
       :<input type="password" name="check_password" id="check_password" />
   <br/>
     :<input type="text" name="email" id="email" />
   <br/>
   <input type="button"   value="  " />
   </form>
 </body>
</html>

javascriptは段落内のテキストを取得します.