javascript

js method to get form

This article illustrates how js gets form. Share to everybody for everybody reference. The details are as follows:

Let’s start with the following code:

<html>
<head>
<scirpy>
window.onload=function(){
   var f1=document.f1;
   var f2=document.forms[1];
 alert(f2.id);
  var f3=document.forms['f1'];
}
</script>
</head>
<body>
<form id="f1" value="f1"></from>
<from id="f2" value="f2"></form>
</body>
</html>

Action form:

<html>
 <head>
 <script>
  function checkform(f){
  var uname=f.username;
  var pwd=f.password;
  if(uname.value.length<4){
  alert(' User length must be greater than 4') ;
  return false;
  }
  if(pwd.value.length!=6){
  alert(' User password must be greater than  6 position ');
  return false;
  }
  return true;
  }
 </script>
 </head>
 <body>
 <form id="f1" name="f1" method="post" action=""
 onsubmit="return checkform(this)">
   <input name="username" value="" /></br>
  <input name="password" value="" /></br>
  <input type="button" value=" submit " />
 </form>
 </body>
</html>

js Three ways to operate form:

1. Use the form’s index in the document or the form’s name attribute to reference the form

document.forms[i]  // Gets the control in the page i A form
document.forms[fromName] // Get the corresponding on the page name The form of

2. Use the id attribute of the form

document.getElementById(formId);
document.formName;// Most commonly used 1 Kind of way

Hopefully, this article has been helpful in your javascript programming.