requestAnimationFrame.js後續學習

標籤：webkit   web   vendor   cancel   ram   gettime   ast   nim   pre   

(function() {  var lastTime = 0;  var vendors = [‘webkit‘, ‘moz‘];  for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {    window.requestAnimationFrame = window[vendors[x] + ‘RequestAnimationFrame‘];    window.cancelAnimationFrame = window[vendors[x] + ‘CancelAnimationFrame‘] ||    // name has changed in Webkit      window[vendors[x] + ‘CancelRequestAnimationFrame‘];  }  if (!window.requestAnimationFrame) {    window.requestAnimationFrame = function(callback, element) {      var currTime = new Date().getTime();      var timeToCall = Math.max(0, 16.7 - (currTime - lastTime));      var id = window.setTimeout(function() {        callback(currTime + timeToCall);      }, timeToCall);      lastTime = currTime + timeToCall;      return id;    };  }  if (!window.cancelAnimationFrame) {    window.cancelAnimationFrame = function(id) {      clearTimeout(id);    };  }}());

 

requestAnimationFrame.js後續學習