![opacity]( "opacity")
Click on a link above to make the image disappear and re-appear by gradually fading in/out. It uses CSS transparency, in CSS you can set the transparency in different ways. To ensure that it works on most browsers we use all three. opacity: 0.5; This one is the official CSS3 method, at the moment it works in newer Mozilla versions. -moz-opacity: 0.5; This one works in older versions of Mozilla and Phoenix/FireBird/FireFox. -khtml-opacity: 0.5; This is used by browsers that use teh KHTML rendering engine, namely Konquerer on Linux and Safari on MacOS. filter: alpha(opacity=50); This one works only in MSIE. There is actually another one: -khtml-opacity: 0.5; works for the browsers Konquerer on Linux and Safari on MacOS. You could add it too if you want to support these users. Somewhere in the near future most browsers will support CSS3 and opacity: 0.5; should work everywhere. 复制代码 代码如下:function opacity(id, opacStart, opacEnd, millisec) { //speed for each frame var speed = Math.round(millisec / 100); var timer = 0; //determine the direction for the blending, if start and end are the same nothing happens if(opacStart > opacEnd) { for(i = opacStart; i >= opacEnd; i--) { setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); timer++; } } else if(opacStart for(i = opacStart; i { setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); timer++; } } } //change the opacity for different browsers function changeOpac(opacity, id) { var object = document.getElementById(id).style; object.opacity = (opacity / 100); object.MozOpacity = (opacity / 100); object.KhtmlOpacity = (opacity / 100); object.filter = "alpha(opacity=" + opacity + ")"; } function shiftOpacity(id, millisec) { //if an element is invisible, make it visible, else make it ivisible if(document.getElementById(id).style.opacity == 0) { opacity(id, 0, 100, millisec); } else { opacity(id, 100, 0, millisec); } } function blendimage(divid, imageid, imagefile, millisec) { var speed = Math.round(millisec / 100); var timer = 0; //set the current image as background document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")"; //make image transparent changeOpac(0, imageid); //make new image document.getElementById(imageid).src = imagefile; //fade in image for(i = 0; i setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed)); timer++; } } function currentOpac(id, opacEnd, millisec) { //standard opacity is 100 var currentOpac = 100; //if the element has an opacity set, get it if(document.getElementById(id).style.opacity currentOpac = document.getElementById(id).style.opacity * 100; } //call for the function that changes the opacity opacity(id, currentOpac, opacEnd, millisec) }更多参考http://www.brainerror.net/scripts_js_blendtrans.phphttp://realazy.org/blog/2006/03/21/ie-firefox-opera-alpha-transparency/ http://alistapart.com/stories/pngopacity/ 08-25 14:57