if(screen.width>1500){
    document.write("<style type='text/css'>");
    document.write("div#cadre-gauche{width:50%;height:100%;position:absolute;top:0px;left:0px;text-align:left;z-index:1;}");
    document.write("div#gauche{position:absolute;top:50%;left:50%;margin-top:-600px;margin-left:-450px;width:900px;height:1200px;}");
        document.write("</style>");
}