Javascript Validation for email (Regular Expression) English Translation

Try testing the following form with valid and invalid email addresses.
Code uses javascript to match the users input with a regular expression.
Function Code: Copy codeThe Code is as follows: function validate (form_id, email ){
Var reg =/^ ([A-Za-z0-9 _ \-\.]) + \ @ ([A-Za-z0-9 _ \-\.]) + \. ([A-Za-z] {2, 4}) $ /;
Var address = document. forms [form_id]. elements [email]. value;
If (reg. test (address) = false ){
Alert ('invalid Email address ');
Return false;
}
}

In the forms 'onsubmit 'code call javascript: return validate ('form _ id', 'email _ field_id ')
Usage:Copy codeThe Code is as follows: <form id = "form_id" method = "post" action = "action. php "onsubmit =" javascript: return validate ('form _ id', 'email '); ">
<Input type = "text" id = "email" name = "email"/>
<Input type = "submit" value = "Submit"/>
</Form>

You shoshould not rely purely on client side validation on your website/web application, if the user has javascript disabled this will not work. Always validate on the server.
From: http://www.white-hat-web-design.co.uk/blog/javascript-validation/