获取屏幕的宽高

function client(){
    if(window.innerHeight !== undefined){
        return {
            "width": window.innerWidth,
            "height": window.innerHeight
        }
    }else if(document.compatMode === "CSS1Compat"){
        return {
            "width": document.documentElement.clientWidth,
            "height": document.documentElement.clientHeight
        }
    }else{
        return {
            "width": document.body.clientWidth,
            "height": document.body.clientHeight
        }
    }
}