You can get the window width with scrollbar , that way:
function scrollbar_width() {
if (jQuery('body').height() > jQuery(window).height()) {
/* Modified from: http://jdsharp.us/jQuery/minute/calculate-scrollbar-width.php */
var calculation_content = jQuery('');
jQuery('body').append(calculation_content);
var width_one = jQuery('div', calculation_content).innerWidth();
calculation_content.css('overflow-y', 'scroll');
var width_two = jQuery('div', calculation_content).innerWidth();
jQuery(calculation_content).remove();
return (width_one - width_two);
}
return 0;
}