Question

Here is my Jsfiddle.

Actually I am trying to validate a text field before it submits.
I want to show the errormsg_box if the text field is empty, if it’s not then submit a form,
but here it is not working
Here is my script:

$("form").submit(function(event) {

    var text_val = $('#emailid').val();
    alert(text_val);
    if (text_val != ' ') {
        $('.errormsg_box').show();
        return false;
        event.preventdefault();
    }
    else if (text_val != '') {
        $('.errormsg_box').hide();
        return true;
    }
});

Answer 1

if ($.trim(text_val) === "") {
    return false;
    // Or
    event.preventDefault(); // event.preventdefault()
                            // javascript is case sensitive.
}

Full code:

$("form").submit(function(event) {
    var text_val = $('#emailid').val();

    if ($.trim(text_val) === "") {
        $('.errormsg_box').show();
        return false;
    }
    else 
        $('.errormsg_box').hide();
});​

Live DEMO

If you want to validte the text is a valid email address:

var regex = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
if (!regex.test($.trim(text_val)))
    ... Error

Live DEMO