js 手机端拖动效果

「已注销」 2017-09-23 10:14:48

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0" />
<style>
body {
height: 2000px;
}
#block {
width:200px;
height:200px;
background-color: red;
position: absolute;
left: 0;
top: 0;
}
</style>
</head>
<body>
<div>
touchstart,touchmove,
touchend,touchcancel
</div>
<div id="block"></div>
<script>
// 获取节点
var block = document.getElementById("block");
var oW,oH;
// 绑定touchstart事件
block.addEventListener("touchstart", function(e) {
console.log(e);
var touches = e.touches[0];
oW = touches.clientX - block.offsetLeft;
oH = touches.clientY - block.offsetTop;
//阻止页面的滑动默认事件
document.addEventListener("touchmove",defaultEvent,false);
},false)

block.addEventListener("touchmove", function(e) {
var touches = e.touches[0];
var oLeft = touches.clientX - oW;
var oTop = touches.clientY - oH;
if(oLeft < 0) {
oLeft = 0;
}else if(oLeft > document.documentElement.clientWidth - block.offsetWidth) {
oLeft = (document.documentElement.clientWidth - block.offsetWidth);
}
block.style.left = oLeft + "px";
block.style.top = oTop + "px";
},false);

block.addEventListener("touchend",function() {
document.removeEventListener("touchmove",defaultEvent,false);
},false);
function defaultEvent(e) {
e.preventDefault();
}
</script>
</body>
</html>

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