Java Script Code:

<script language="javascript"> function validation(myform) { if(myform.password.value!=myform.confirmpassword.value ) { alert("Confirm Password doesn't match"); myform.confirmpassword.focus(); return false; } } </script>

 
In body of html:

<form name="NewUserRegistration" action="registration_save.php" method="post" onSubmit="return validation(this)"> <input type="password" name="password" /> <input type="password" name="confirmpassword" /> <input type="submit" name="Submit" value="Register" /> </form>