iscroll是移端端开发的两大利器之一（另一个是fastclick），为了将它整合的avalon，需要对它认真学习一番。下面是我的笔记。
第一天看的是它的工具类util.js
//用于做函数节流
var rAF = window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function (callback) { window.setTimeout(callback, 1000 / 60); };
var utils = (function () {
var me = {};
var _elementStyle = document.createElement('div').style;
//取得可以用的私有前缀
var _vendor = (function () {
var vendors = ['t', 'webkitT', 'MozT', 'msT', 'OT'],
transform,
i = 0,
l = vendors.length;
for ( ; i 0 ) {
destination = wrapperSize ? wrapperSize / 2.5 * ( speed / 8 ) : 0;
distance = Math.abs(current) + destination;
duration = distance / speed;
}
return {
destination: Math.round(destination),
duration: duration
};
};
//取得可以用transform样式名
var _transform = _prefixStyle('transform');
me.extend(me, {
hasTransform: _transform !== false,//判定浏览器是否支持CSS3 transform
hasPerspective: _prefixStyle('perspective') in _elementStyle,//支持透视效果
hasTouch: 'ontouchstart' in window,//是否是触摸屏
hasPointer: window.PointerEvent || window.MSPointerEvent, // IE10 is prefixed
hasTransition: _prefixStyle('transition') in _elementStyle//支持CSS3渐变
});
// This should find all Android browsers lower than build 535.19 (both stock browser and webview)
//判定安卓的浏览器是否版本过低
me.isBadAndroid = /Android /.test(window.navigator.appVersion) && !(/Chrome\/\d/.test(window.navigator.appVersion));
me.extend(me.style = {}, {//修正与CSS3变渐相关的样式名
transform: _transform,
transitionTimingFunction: _prefixStyle('transitionTimingFunction'),
transitionDuration: _prefixStyle('transitionDuration'),
transitionDelay: _prefixStyle('transitionDelay'),
transformOrigin: _prefixStyle('transformOrigin')
});
//操作类名的三个常用方法
me.hasClass = function (e, c) {
var re = new RegExp("(^|\\s)" + c + "(\\s|$)");
return re.test(e.className);
};
me.addClass = function (e, c) {
if ( me.hasClass(e, c) ) {
return;
}
var newclass = e.className.split(' ');
newclass.push(c);
e.className = newclass.join(' ');
};
me.removeClass = function (e, c) {
if ( !me.hasClass(e, c) ) {
return;
}
var re = new RegExp("(^|\\s)" + c + "(\\s|$)", 'g');
e.className = e.className.replace(re, ' ');
};
me.offset = function (el) {
var left = -el.offsetLeft,
top = -el.offsetTop;
// jshint -W084
while (el = el.offsetParent) {
left -= el.offsetLeft;
top -= el.offsetTop;
}
// jshint +W084
return {
left: left,
top: top
};
};
me.preventDefaultException = function (el, exceptions) {
for ( var i in exceptions ) {
if ( exceptions[i].test(el[i]) ) {
return true;
}
}
return false;
};
//四套事件名
me.extend(me.eventType = {}, {
touchstart: 1,
touchmove: 1,
touchend: 1,
mousedown: 2,
mousemove: 2,
mouseup: 2,
pointerdown: 3,
pointermove: 3,
pointerup: 3,
MSPointerDown: 3,
MSPointerMove: 3,
MSPointerUp: 3
});
//各种缓动公式
me.extend(me.ease = {}, {
quadratic: {
style: 'cubic-bezier(0.25, 0.46, 0.45, 0.94)',
fn: function (k) {
return k * ( 2 - k );
}
},
circular: {
style: 'cubic-bezier(0.1, 0.57, 0.1, 1)', // Not properly "circular" but this looks better, it should be (0.075, 0.82, 0.165, 1)
fn: function (k) {
return Math.sqrt( 1 - ( --k * k ) );
}
},
back: {
style: 'cubic-bezier(0.175, 0.885, 0.32, 1.275)',
fn: function (k) {
var b = 4;
return ( k = k - 1 ) * k * ( ( b + 1 ) * k + b ) + 1;
}
},
bounce: {
style: '',
fn: function (k) {
if ( ( k /= 1 )
源码还算易读，但也遇到几个不懂的地方。一个是momentum方法，物理公式忘光了，另一个是offset方法。offset的结果与我们常用的不一致。
<!DOCTYPE html>
<html>
<head>
<title>iscroll学习 by 司徒正美</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script src="avalon.js" ></script>
<script>
window.onload = function() {
var elem = document.querySelector("#son")
var offset = function(el) {
var left = -el.offsetLeft,
top = -el.offsetTop;
// jshint -W084
while (el = el.offsetParent) {
left -= el.offsetLeft;
top -= el.offsetTop;
}
// jshint +W084
return {
left: left,
top: top
};
};
console.log(offset(elem)) //iscroll.offset 返回 [-400,-400]
console.log(avalon(elem).offset()) //jQuery.offset, avalon.offset返回 [400, 400]
}
</script>
</head>
<body>
<style>
#parent{
position: absolute;
top:200px;
left:200px;
}
#son {
position: absolute;
top:200px;
left:200px;
}
</style>
<div ms-controller="test">
<div >
<input />ddd
</div
</div>
</body>
</html>