js里面设置DOM节点透明度的函数属性：filter= "alpha(opacity=" + value+ ")"（兼容ie）和opacity=value/100（兼容FF和GG）。
先来看看设置透明度的兼容性代码：
function setOpacity(ele, opacity) { if (ele.style.opacity != undefined) { ///兼容FF和GG和新版本IE ele.style.opacity = opacity / 100; } else { ///兼容老版本ie ele.style.filter = "alpha(opacity=" + opacity + ")"; } }
关于有的小伙伴这样写：
function setOpacity(ele, opacity) { if (document.all) { ///兼容ie ele.style.filter = "alpha(opacity=" + opacity + ")"; } ele { ///兼容FF和GG ele.style.opacity = opacity / 100; } }
我想说这样在IE10下运行有问题，点了之后没反应。因为IE10支持opacity属性不支持filter了，这个方法不可取。
fadein 函数代码：
function fadein(ele, opacity, speed) { if (ele) { var v = ele.style.filter.replace("alpha(opacity=", "").replace(")", "") || ele.style.opacity; v < 1 && (v = v * 100); var count = speed / 1000; var avg = count < 2 ? (opacity / count) : (opacity / count - 1); var timer = null; timer = setInterval(function() { if (v < opacity) { v += avg; setOpacity(ele, v); } else { clearInterval(timer); } }, 500); } }
fadeout 函数代码：
function fadeout(ele, opacity, speed) { if (ele) { var v = ele.style.filter.replace("alpha(opacity=", "").replace(")", "") || ele.style.opacity || 100; v < 1 && (v = v * 100); var count = speed / 1000; var avg = (100 - opacity) / count; var timer = null; timer = setInterval(function() { if (v - avg > opacity) { v -= avg; setOpacity(ele, v); } else { clearInterval(timer); } }, 500); } }
下面给一个demo示例：
<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title></title> <script type="text/javascript" src="fade.js"></script> <script type="text/javascript"> window.onload = function () { document.getElementById('Button1').onclick = function () { fadeout(document.getElementById('DV'), 0, 6000); } document.getElementById('Button2').onclick = function () { fadein(document.getElementById('DV'), 80, 6000); } } </script> </head> <body> <div id="DV" style="background-color: green; 400px; height: 400px;"></div> <input id="Button1" type="button" value="button" /> <input id="Button2" type="button" value="button" /> </body> </html>
有什么更好的实现方式可以留言。。。