本文实例讲述了js实现类似jquery里animate动画效果的方法。分享给大家供大家参考。具体分析如下:
该实例可实现鼠标移上,先宽度变化,再高度变化,最后透明度变化,鼠标移出,再依次变回去的效果。
要点一:
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,函数也可以做为参数使用,就可以达到先执行某个动作,再执行某个动作的效果了。
要点二:
if(cur == target){clearInterval(obj.timer);if(fn){fn();}}
当运动到达目标点,关闭定时器,然后就可以执行新的函数了。
最后,上代码:
<!DOCTYPE html><html><head><meta charset="gb2312" /><title>无标题文档</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>
希望本文所述对大家的javascript程序设计有所帮助。
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