做到这个很简单
直接将以下代码加到网站底部就完工了

代码如下：

<script>
$('body').before('<div id="fps" style="z-index:10000;position:fixed;top:3;left:3;font-weight:bold;"></div>');
var showFPS = (function(){ 
    var requestAnimationFrame =  
        window.requestAnimationFrame || 
        window.webkitRequestAnimationFrame || 
        window.mozRequestAnimationFrame ||
        window.oRequestAnimationFrame ||
        window.msRequestAnimationFrame || 
        function(callback) { 
            window.setTimeout(callback, 1000/60); 
        }; 
    var e,pe,pid,fps,last,offset,step,appendFps; 
fps = 0; 
last = Date.now(); 
step = function(){ 
    offset = Date.now() - last; 
    fps += 1; 
    if( offset &gt;= 1000 ){ 
    last += offset; 
    appendFps(fps); 
    fps = 0; 
    } 
    requestAnimationFrame( step ); 
}; 
appendFps = function(fps){ 
    console.log(fps+'FPS');
    $('#fps').html(fps+'FPS');
};
step();

})();
</script>