无法使用JavaScript或jQuery设置隐藏的表单字段

Question

I have a Form that uses JavaScript to get the browser/client Time Zone Offset value, I then need to set that value to a Form field so that when the Form is POSTED, it will send to my backend script.

I can alert(clientTimeOffset) with my code below and it alerts the correct value, however when I submit a form, it never set the hidden form field with that value so it never gets posted.

Below is all the code I have tried so far, any help please?

Version 1

jQuery( document ).ready(function() {

    // Set TimeZone Offset Form Value
    var d = new Date();
    var clientTimeOffset = (d.getTimezoneOffset()/ 60 *(-1))+5;
    jQuery("#timezone").val(clientTimeOffset);

});

Version 2

jQuery( document ).ready(function() {

    // Set TimeZone Offset Form Value
    var d = new Date();
    var clientTimeOffset = (d.getTimezoneOffset()/ 60 *(-1))+5;
    var x = document.getElementById("timezone");
    x.value=clientTimeOffset;

});

My Form Field...

<input type="hidden" name="timezone" id="timezone" />

Answer 1

I feel silly but the problem was, somehow I had 2 hidden form fields with the same #ID, so it would set the first value and then the second one would overwrite it as empty when the POST was made. Maybe this will help someone someday, make sure you only have 1 form field that the selector matches!