js拖动滑块
在PC端可以用mousedown来触发一个滑块滑动的效果，但在手机上，貌似无法识别这个事件，但手机上有touchstart事件，可以通过一系列“touch”事件来替代PC端的“mouse”事件。
移动端触屏滑动的效果其实就是图片轮播，在PC的页面上很好实现，绑定click和mouseover等事件来完成。但是在移动设备上，要实现这种轮播的效果，就需要用到核心的touch事件。处理touch事件能跟踪到屏幕滑动的每根手指。
以下是四种touch事件
touchstart: //手指放到屏幕上时触发
touchmove: //手指在屏幕上滑动式触发
touchend: //手指离开屏幕时触发
touchcancel: //系统取消touch事件的时候触发，这个好像比较少用
每个触摸事件被触发后，会生成一个event对象，event对象里额外包括以下三个触摸列表
touches: //当前屏幕上所有手指的列表
targetTouches: //当前dom元素上手指的列表，尽量使用这个代替touches
changedTouches: //涉及当前事件的手指的列表，尽量使用这个代替touches
这些列表里的每次触摸由touch对象组成，touch对象里包含着触摸信息，主要属性如下：
clientX / clientY: //触摸点相对浏览器窗口的位置
pageX / pageY: //触摸点相对于页面的位置
screenX / screenY: //触摸点相对于屏幕的位置
identifier: //touch对象的ID
target: //当前的DOM元素
兼容pc和移动端：
<!DOCTYPE html>
<html lang="zh-cn">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
<title>鼠标拖动小方块</title>
<style type="text/css">
.lineDiv {
position: relative;
height: 5px;
background: red;
width: 300px;
margin: 50px auto;
}
.lineDiv .minDiv {
position: absolute;
top: -5px;
left: 0;
width: 15px;
height: 15px;
background: green;
cursor: pointer
}
.lineDiv .minDiv .vals {
position: absolute;
font-size: 20px;
top: -45px;
left: -10px;
width: 35px;
height: 35px;
line-height: 35px;
text-align: center;
background: blue;
}
.lineDiv .minDiv .vals:after {
content: "";
width: 0px;
height: 0px;
border-top: 6px solid blue;
border-left: 6px solid transparent;
border-right: 6px solid transparent;
border-bottom: 6px solid transparent;
display: block;
margin-left: 11px;
}
</style>
</head>
<body>
<center>
<h3>用鼠标拖动小方块<span id="msg">0</span>%</h3>
</center>
<div id="lineDiv" class="lineDiv">
<div id="minDiv" class="minDiv">
<div id="vals" class="vals">0</div>
</div>
</div>
<script>
window.onload = function() {
var lineDiv = document.getElementById('lineDiv'); //长线条
var minDiv = document.getElementById('minDiv'); //小方块
var msg = document.getElementById("msg");
var vals = document.getElementById("vals");
var ifBool = false; //判断鼠标是否按下
//事件
var start = function(e) {
e.stopPropagation();
ifBool = true;
console.log("鼠标按下")
}
var move = function(e) {
console.log("鼠标拖动")
if(ifBool) {
if(!e.touches) { //兼容PC端
var x = e.clientX;
} else { //兼容移动端
var x = e.touches[0].pageX;
}
//var x = e.touches[0].pageX || e.clientX; //鼠标横坐标var x
var lineDiv_left = getPosition(lineDiv).left; //长线条的横坐标
var minDiv_left = x - lineDiv_left; //小方块相对于父元素（长线条）的left值
if(minDiv_left >= lineDiv.offsetWidth - 15) {
minDiv_left = lineDiv.offsetWidth - 15;
}
if(minDiv_left < 0) {
minDiv_left = 0;
}
//设置拖动后小方块的left值
minDiv.style.left = minDiv_left + "px";
msg.innerText = parseInt((minDiv_left / (lineDiv.offsetWidth - 15)) * 100);
vals.innerText = parseInt((minDiv_left / (lineDiv.offsetWidth - 15)) * 100);
}
}
var end = function(e) {
console.log("鼠标弹起")
ifBool = false;
}
//鼠标按下方块
minDiv.addEventListener("touchstart", start);
minDiv.addEventListener("mousedown", start);
//拖动
window.addEventListener("touchmove", move);
window.addEventListener("mousemove", move);
//鼠标松开
window.addEventListener("touchend", end);
window.addEventListener("mouseup", end);
//获取元素的绝对位置
function getPosition(node) {
var left = node.offsetLeft; //获取元素相对于其父元素的left值var left
var top = node.offsetTop;
current = node.offsetParent; // 取得元素的offsetParent
// 一直循环直到根元素
while(current != null) {
left += current.offsetLeft;
top += current.offsetTop;
current = current.offsetParent;
}
return {
"left": left,
"top": top
};
}
}
</script>
</body>
</html>
<!DOCTYPE html><html lang="zh-cn"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" /> <title>鼠标拖动小方块</title> <style type="text/css"> .lineDiv { position: relative; height: 5px; background: red; width: 300px; margin: 50px auto; } .lineDiv .minDiv { position: absolute; top: -5px; left: 0; width: 15px; height: 15px; background: green; cursor: pointer } .lineDiv .minDiv .vals { position: absolute; font-size: 20px; top: -45px; left: -10px; width: 35px; height: 35px; line-height: 35px; text-align: center; background: blue; } .lineDiv .minDiv .vals:after { content: ""; width: 0px; height: 0px; border-top: 6px solid blue; border-left: 6px solid transparent; border-right: 6px solid transparent; border-bottom: 6px solid transparent; display: block; margin-left: 11px; } </style> </head> <body> <center> <h3>用鼠标拖动小方块<span id="msg">0</span>%</h3> </center> <div id="lineDiv" class="lineDiv"> <div id="minDiv" class="minDiv"> <div id="vals" class="vals">0</div> </div> </div> <script> window.onload = function() { var lineDiv = document.getElementById('lineDiv'); //长线条 var minDiv = document.getElementById('minDiv'); //小方块 var msg = document.getElementById("msg"); var vals = document.getElementById("vals"); var ifBool = false; //判断鼠标是否按下 //事件 var start = function(e) { e.stopPropagation(); ifBool = true; console.log("鼠标按下") } var move = function(e) { console.log("鼠标拖动") if(ifBool) { if(!e.touches) { //兼容移动端 var x = e.clientX; } else { //兼容PC端 var x = e.touches[0].pageX; } //var x = e.touches[0].pageX || e.clientX; //鼠标横坐标var x var lineDiv_left = getPosition(lineDiv).left; //长线条的横坐标 var minDiv_left = x - lineDiv_left; //小方块相对于父元素（长线条）的left值 if(minDiv_left >= lineDiv.offsetWidth - 15) { minDiv_left = lineDiv.offsetWidth - 15; } if(minDiv_left < 0) { minDiv_left = 0; } //设置拖动后小方块的left值 minDiv.style.left = minDiv_left + "px"; msg.innerText = parseInt((minDiv_left / (lineDiv.offsetWidth - 15)) * 100); vals.innerText = parseInt((minDiv_left / (lineDiv.offsetWidth - 15)) * 100); } } var end = function(e) { console.log("鼠标弹起") ifBool = false; } //鼠标按下方块 minDiv.addEventListener("touchstart", start); minDiv.addEventListener("mousedown", start); //拖动 window.addEventListener("touchmove", move); window.addEventListener("mousemove", move); //鼠标松开 window.addEventListener("touchend", end); window.addEventListener("mouseup", end); //获取元素的绝对位置 function getPosition(node) { var left = node.offsetLeft; //获取元素相对于其父元素的left值var left var top = node.offsetTop; current = node.offsetParent; // 取得元素的offsetParent // 一直循环直到根元素 while(current != null) { left += current.offsetLeft; top += current.offsetTop; current = current.offsetParent; } return { "left": left, "top": top }; } } </script> </body></html>