js 获取窗口大小

function getWin(){

             //获取窗口宽度
             if (document.body){
                   winWidth = document.body.clientWidth;
                    winHeight = document.body.clientHeight;
                   }
         
             else if (document.documentElement)
             {
                 winHeight = document.documentElement.clientHeight;
                 winWidth = document.documentElement.clientWidth;
             }
             return[winWidth,winHeight]
            

}