該實例可實現鼠標移上，先寬度變化，再高度變化，最後透明度變化，鼠標移出，再依次變回去的效果。
要點一：
1 2 3 4 5 6 7 8 startrun(obj,attr,target,fn) box.onmouseover = function(){ startrun(box,"width",200,function(){ startrun(box,"height",200,function(){ startrun(box,"opacity","100") }); }); }如上面，函數也可以做為參數使用，就可以達到先執行某個動作，再執行某個動作的效果了。
要點二：
1 2 3 4 5 6 if(cur == target){ clearInterval(obj.timer); if(fn){ fn(); } }當運動到達目標點，關閉定時器，然後就可以執行新的函數了。
最後，上代碼：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 <!DOCTYPE html> <html> <head> <meta charset="gb2312" /> <title>無標題文檔</title> <style> <!-- body{margin:0; padding:0; font:12px/1.5 arial;} #box{width:100px; height:100px; position:absolute; background:#06c; left:0;filter:alpha(opacity=30); opacity:0.3;} --> </style> <script> <!-- function getstyle(obj,name){ if(obj.currentStyle){ return obj.currentStyle[name]; }else{ return getComputedStyle(obj,false)[name]; } } window.onload = function(){ var box = document.getElementById("box"); box.onmouseover = function(){ startrun(box,"width",200,function(){ startrun(box,"height",200,function(){ startrun(box,"opacity","100") }); }); } box.onmouseout = function(){ startrun(box,"height",100,function(){ startrun(box,"width",100,function(){ startrun(box,"opacity","30"); }); }); } } function startrun(obj,attr,target,fn){ clearInterval(obj.timer); obj.timer = setInterval(function(){ var cur = 0; if(attr == "opacity"){ cur = Math.round(parseFloat(getstyle(obj,attr))*100); }else{ cur = parseInt(getstyle(obj,attr)); } var speed = (target-cur)/8; speed = speed>0?Math.ceil(speed):Math.floor(speed); if(cur == target){ clearInterval(obj.timer); if(fn){ fn(); } }else{ if(attr == "opacity"){ obj.style.filter = "alpha(opacity="+(cur+speed)+")"; obj.style.opacity = (cur+speed)/100; }else{ obj.style[attr] = cur + speed + "px"; } } },30) } //--> </script> </head> <body> <div id="box"> </div> </body> </html>