enable disable field with checkbox

Trying to disable input fields and buttons with checkbox

HTML

<h4>Random or Not </h4>

<!-- Use Random Image -->  

<label><input name="o99_aufu_options[o99_aufu_random]" id="o99_aufu_options[o99_aufu_random]" value="1" checked="checked" type="checkbox">Use Random Image ? <em></em></label><br>  

<!-- If the above not checked - needs to be enabled -->                         
Upload Image <label for="upload_image"> <input id="upload_image" size="36" name="o99_aufu_options[o99_aufu_upload_image]" value="" type="text"> <input id="upload_image_button" value="Choose Image or upload" type="button"> </label>

JavaScript

if (jQuery('#o99_aufu_options[o99_aufu_random]').is(':checked')) {
       jQuery('#upload_image :input').attr('disabled', true);
    } else {
        jQuery('#upload_image_button,#upload_image :input').removeAttr('disabled');
    }