I have input name="email" and a button on the page.

How do I validate this input in live for a valid email address? And add some class for a button, class "active" if it is valid or "inactive".

This is a small task, so I don't want to use a plugins.

Thanks

I have input name="email" and a button on the page.

How do I validate this input in live for a valid email address? And add some class for a button, class "active" if it is valid or "inactive".

This is a small task, so I don't want to use a plugins.

Thanks

• javascript
• jquery
• html
• validation
• forms

• 1 The fact that it is a small task is no reason not to use a well-tested plugin that will save you time. docs.jquery./Plugins/… – Chris Shouts Commented Apr 25, 2011 at 13:16
• @Chris - using a plugin to validate a single field (that doesn't need validation anyway) doesn't make sense. @Steve - the best way to validate an email address is to send an email to it. Using a regular expression (or any other kind of parsing) is unreliable and not worth doing. – RobG Commented Apr 25, 2011 at 14:02
• Using jQuery Validade plugin is very easy docs.jquery./Plugins/validation – msmafra Commented Apr 25, 2011 at 15:50

3 Answers 3

I usually use this javascript function to validate in frontend:

function validateEmail(email) 
{ 
 var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/ 
 return email.match(re) 
}

it returns true or false. But anyway, you shouldn't usually only validate sensitive data in the frontend, but also on the server side.

$('#email').bind('keyup', function(){
    if(this.value.test([REGULAR_EXPRESSION])
        //doStuff -- add active class
    else
        //doOtherStuff -- add inactive class
});

replace [REGULAR_EXPRESSION] with one of the regular expressions found here: http://www.regular-expressions.info/email.html

i used this for mail validation javascript mail code

    function ValidateEmail(inputText)
    {
    var mailformat = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
    if(inputText.value.match(mailformat))
    {
    document.form1.text1.focus();
    return true;
    }
    else
    {
    alert("You have entered an invalid email address!");
    document.form1.text1.focus();
    return false;
    }
  }