本文實例講述了js實現同一個頁面多個漸變效果的方法。分享給大家供大家參考。具體分析如下：
這里可實現5個元素中隨便一個，鼠標移上去透明度漸漸增加，鼠標移出，透明度漸漸減小的效果。
要點一：
var speed = 0;if(target>obj.alpha){speed = 5;}else{speed = -5;}根據目標值和當時值的對比，來決定是正向還是負向速度。
要點二：
for(i=0; i<runs_li.length; i++){runs_li[i].timer = null;runs_li[i].alpha = 30;runs_li[i].onmouseover = function(){startrun(this,100);}runs_li[i].onmouseout = function(){startrun(this,30);}}給每一個元素加上各自的透明度值，各自的透明度變化分開。
最后，上代碼：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>無標題文檔</title><style>body,ul,li{margin:0; padding:0;}#runs{width:300px; margin:10px auto;}#runs li{width:80px; height:80px; background:#06c; list-style:none;float:left; margin:10px; display:inline;filter:alpha(opacity=30); opacity:0.3;}</style><script>window.onload = function(){ var runs = document.getElementById("runs"); var runs_li = runs.getElementsByTagName("li"); var i=0; for(i=0; i<runs_li.length; i++){ runs_li[i].timer = null; runs_li[i].alpha = 30; runs_li[i].onmouseover = function(){ startrun(this,100); } runs_li[i].onmouseout = function(){ startrun(this,30); } }}function startrun(obj,target){ clearInterval(obj.timer); obj.timer = setInterval(function(){ var speed = 0; if(target>obj.alpha){ speed = 5; }else{ speed = -5; } if(obj.alpha == target){ clearInterval(obj.timer); }else{ obj.alpha = obj.alpha + speed; obj.style.filter = "alpha(opacity="+obj.alpha+")"; obj.style.opacity = obj.alpha/100; } },30)}</script></head><body><ul id="runs"> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li></ul></body></html>希望本文所述對大家的javascript程序設計有所幫助。
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