<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> img { border: none; opacity: 0.3; filter: alpha(opacity:30); position: absolute; left: 200px; } #box { width: 150px; height: 300px; background: red; position: absolute; left: -150px; top: 50px; } #box div { width: 28px; height: 100px; position: absolute; right: -28px; top: 100px; background: green; } </style> <script> window.onload = function () { var oImg = document.getElementById("img"), oBox = document.getElementById("box"); oImg.onmouseover = function () { animate(this, 'opacity', 100, 10); } oImg.onmouseout = function () { animate(this, 'opacity', 30, -10); } oBox.onmouseover = function () { animate(this, 'left', 0, 10); } oBox.onmouseout = function () { animate(this, 'left', -150, -10); } function animate(obj, attr, target, speed) { clearInterval(obj.timer); var cur = 0; obj.timer = setInterval(function () { if (attr == 'opacity') { cur = css(obj, 'opacity') * 100; } else { cur = parseInt(css(obj, attr)); } if (cur == target) { clearInterval(obj.timer); } else { if (attr == 'opacity') { obj.style.opacity = ( cur + speed ) / 100; obj.style.filter = "alpha(opacity:" + (cur + speed) + ")"; } else { obj.style[attr] = cur + speed + "px"; } } }, 30); } function css(obj, attr) { if (obj.currentStyle) { return obj.currentStyle[attr]; } else { return getComputedStyle(obj, false)[attr]; } } } </script> </head> <body> <div> <div>分享到</div> </div> <img src="https://www.jb51.net/article/img/h4.jpg" alt=""/> </body> </html>
至此，我们就完成了多物体运动与不同样式的修改
二、让animate函数支持多个样式同时改变
比如：
oBox.onmouseover = function(){ animate( this, { "width" : 500, "height" : 400 }, 10 ); }
oBox是一个div元素，animate各参数的意思：
this: 当前div元素
{width : 500, "height" : 400 } : 把宽度变成500, 高度变成400，这两个样式要在同一时间完成，
10: 样式每次在原来的基础上变化10（如width初始值200--> 210, 220, 230.....）
完整的同时运动变化 代码：
<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Document</title> <style> div { width: 200px; height: 200px; background: red; } </style> <script> window.onload = function () { var oBox = document.getElementById("box"); oBox.onmouseover = function(){ // animate( this, { "width" : 500, "height" : 500 }, 10 ); animate( this, { "width" : 500, "height" : 400 }, 10 ); } function animate(obj, attr, speed) { clearInterval(obj.timer); var cur = 0; obj.timer = setInterval(function () { for ( var key in attr ) { if (key == 'opacity') { cur = css(obj, 'opacity') * 100; } else { cur = parseInt(css(obj, key)); } var target = attr[key]; if (cur == target) { clearInterval(obj.timer); } else { if (key == 'opacity') { obj.style.opacity = ( cur + speed ) / 100; obj.style.filter = "alpha(opacity:" + (cur + speed) + ")"; } else { obj.style[key] = cur + speed + "px"; } } } }, 30); } function css(obj, attr) { if (obj.currentStyle) { return obj.currentStyle[attr]; } else { return getComputedStyle(obj, false)[attr]; } } } </script> </head> <body> <div></div> </body> </html>
请自行展开这段代码，这段代码能够同时运动，但是有一个问题：
div的初始宽度与高度（ width : 200, height : 200）
变化步长一样( 10 )
变化时间一样( 每30毫秒变化一次 )
目标( width: 500, height : 400 )
你能想到什么问题吗？( 两个人在同一起跑线上，速度一样， 时间一样，但是要同时到达不同的目标，一个500, 一个400 )
答案是很明显的，肯定是目标近的( height : 400 )那个先到达，然后把对象上的定时器关了，另一个目标更远的( width: 500 )肯定到达不了
你可以在这句代码下面，输出当前的值和目标值：
var target = attr[key]; console.log( key, cur, target );
输出来的结果是：
