Question

I am facing a problem that when I submit the page (form) the submission to php mail is success but the page again reloads. Tried return true and false also preventDefault() but still the page reloads.

$('#frmRequest').submit(function(e){
    //$('#SUBMIT').click(function(){
    var isValidForm = true;
    $('#RequestDetailsArea').find('input:visible, textarea:visible, select:visible').each(function(){
        if( $(this).val().length == 0|| $(this).val()=='Select' ) {
            $(this).addClass('validation');
            isValidForm = false;      
        }
        else {
            $(this).removeClass('validation'); 
            $('#ErrorRequest').addClass('hidden');           
        }
    });/* end check validation in RequestDetailsArea*/
    if (!isValidForm) {
        $('#ErrorRequest').removeClass('hidden');   
    }
    validreturn=validateForm();
    if(isValidForm && validreturn)
    {
        $('#RequestDetailsArea').find('div:hidden').each(function(){
            //alert($(this).attr('id'));
            $(this).remove();
        });

        msg="ok";
        $.ajax({
            url:"allfields.php",
            type:"POST",
            //      dataType:"json",
            data: $("#frmRequest").serialize(),
            success: function(msg){
                //alert("Form Submitted: "+ msg);
                return msg;

            },
            error: function() {
                alert('Error occured');
            }
        });
        e.preventDefault();

        //return false;
    }
});/* end of submit Function*/

Answer 1

In your code you have put e.preventDefault(); inside

if(isValidForm && validreturn)
{
    //...
    e.preventDefault();
}

So I think if your condition doesn’t match then the form will be submitted because the calling of method e.preventDefault(); won’t be executed. If this is the case then you can keep it out of your if condition, i.e,

$('#frmRequest').submit(function(e){
    e.preventDefault();
    // rest of your code here
});

Update: You are using return msg in your success, that will do nothing, you can do it in this way

success: function(msg){
    returnValue(msg); // call the function      
}

and declare the returnValue somewhere in the script like

function returnValue(data)
{
    // do something with data
}