取消双击上滑(针对iso)

var agent = navigator.userAgent.toLowerCase();
var iLastTouch = null;
if (agent.indexOf("iphone") >= 0 || agent.indexOf("ipad") >= 0) {
document.body.addEventListener("touchend", function (event) {
var a = new Date().getTime();
iLastTouch = iLastTouch || a + 1;
var c = a - iLastTouch;
if (c < 500 && c > 0) {
event.preventDefault();
return false;
}
iLastTouch = a
}, false);
};