$.scrollbarWidth = function () {

    var parent, child, width;

    if (width === undefined) {

        parent = $('<div style="width:50px;height:50px;overflow:auto"><div/></div>').appendTo('body');

        child = parent.children();

        width = child.innerWidth() - child.height(99).innerWidth();

        parent.remove();

    }

    return width;

};

function setWidth() {

    var scrollbarwidth = $.scrollbarWidth();

    $('#targetDiv').css({ 'width': ($('#srcDiv').width() - scrollbarwidth) + "px" });

}