upate()为什么要写的那么复杂,向下面那种写法不行吗

其它的地方都一样

window.onload = function(){

var canvas = document.getElementById("myCanvas");

var context = canvas.getContext("2d");

canvas.width = WINDOW_WIDTH;

canvas.height = WINDOW_HEIGHT;

curShowTimeSeconds = getCurrentShowTimeSeconds();

render(context);

setInterval(function(){

curShowTimeSeconds = getCurrentShowTimeSeconds();

render(context);

},1000);

}