Question

New to javascript, but I’m sure this is easy. Unfortunately, most of the google results haven’t been helpful.

Anyway, I want to set the value of a hidden form element through javascript when a drop down selection changes.

I can use jQuery, if it makes it simpler to get or set the values.

Answer 1

If you have HTML like this, for example:

<select id='myselect'>
    <option value='1'>A</option>
    <option value='2'>B</option>
    <option value='3'>C</option>
    <option value='4'>D</option>
</select>
<input type='hidden' id='myhidden' value=''>

All you have to do is bind a function to the change event of the select, and do what you need there:

<script type='text/javascript'>
$(function() {
    $('#myselect').change(function() {
        // if changed to, for example, the last option, then
        // $(this).find('option:selected').text() == D
        // $(this).val() == 4
        // get whatever value you want into a variable
        var x = $(this).val();
        // and update the hidden input's value
        $('#myhidden').val(x);
    });
});
</script>

All things considered, if you’re going to be doing a lot of jQuery programming, always have the documentation open. It is very easy to find what you need there if you give it a chance.