写个定时器,定时减少一个图片或者一个有颜色的div的width,其实原理就是这么简单

解决方案 »

  1.   

    写个定时器执行函数 
    <div id="b" name="b"><div>for(i=0;i<29;i++){
    var aaa="||||||||||||||||||||||||||||||";
    aaa.length=aaa.length-1;
    document.b.innerHTML=aaa;}
      

  2.   

    <style type="text/css">
    #divLoadCont{position:absolute; z-index:500; left:0; top:0; width:100%; height:98%; clip:rect(0,100%,100%,0); background-color:transparent; layer-background-color:white; }
    #divLoad1{position:absolute; layer-background-color:silver; background-color:silver}
    #divLoad2{position:absolute; left:0; top:0; layer-background-color:navy; background-color:navy}
    #divLoadText{position:absolute; background-color:transparent; font-family:arial,helvetica; color:Navy; font-size:14px; } 
    </style>
    <script language="JavaScript" type="text/javascript">
    function lib_bwcheck(){ //Browsercheck (needed)
            this.ver=navigator.appVersion
            this.agent=navigator.userAgent
            this.dom=document.getElementById?1:0
            this.opera5=this.agent.indexOf("Opera 5")>-1
            this.ie5=(this.ver.indexOf("MSIE 5")>-1 && this.dom && !this.opera5)?1:0; 
            this.ie6=(this.ver.indexOf("MSIE 6")>-1 && this.dom && !this.opera5)?1:0;
            this.ie4=(document.all && !this.dom && !this.opera5)?1:0;
            this.ie=this.ie4||this.ie5||this.ie6
            this.mac=this.agent.indexOf("Mac")>-1
            this.ns6=(this.dom && parseInt(this.ver) >= 5) ?1:0; 
            this.ns4=(document.layers && !this.dom)?1:0;
            this.bw=(this.ie6 || this.ie5 || this.ie4 || this.ns4 || this.ns6 || this.opera5)
            return this
    }
    var bw=new lib_bwcheck()
    numImages=50 //速度
    loaderWidth=300 //进度条长度currentImg=0
    function lib_doc_size(){ 
      this.x=0;this.x2=bw.ie && document.body.offsetWidth-20||innerWidth||0;
      this.y=0;this.y2=bw.ie && document.body.offsetHeight-5||innerHeight||0;
      if(!this.x2||!this.y2) return message('Document has no width or height') 
      this.x50=this.x2/2;this.y50=this.y2/2;
      return this;
    }
    function lib_obj(obj,nest){ 
      nest=(!nest) ? "":'document.'+nest+'.'
      this.evnt=bw.dom? document.getElementById(obj):bw.ie4?document.all[obj]:bw.ns4?eval(nest+"document.layers." +obj):0;        
      this.css=bw.dom||bw.ie4?this.evnt.style:this.evnt; 
      this.ref=this.css
      this.w=this.evnt.offsetWidth||this.css.clip.width||
        this.ref.width||this.css.pixelWidth||0; 
      return this
    }
    lib_obj.prototype.moveIt = function(x,y){
      this.x=x;this.y=y; this.css.left=x;this.css.top=y
    }
    lib_obj.prototype.clipTo = function(t,r,b,l,setwidth){ 
      this.ct=t; this.cr=r; this.cb=b; this.cl=l
      if(bw.ns4){
        this.css.clip.top=t;this.css.clip.right=r
        this.css.clip.bottom=b;this.css.clip.left=l
      }else{
        if(t<0)t=0;if(r<0)r=0;if(b<0)b=0;if(b<0)b=0
        this.css.clip="rect("+t+","+r+","+b+","+l+")";
        if(setwidth){this.css.pixelWidth=this.css.width=r; 
        this.css.pixelHeight=this.css.height=b}
      }
    }
    var oLoad2
    function startLoading(){
      page=new lib_doc_size()
      oLoadCont=new lib_obj('divLoadCont')
      oLoad=new lib_obj('divLoad1','divLoadCont')
      oLoad2=new lib_obj('divLoad2','divLoadCont.document.divLoad1')
      oLoadText=new lib_obj('divLoadText','divLoadCont.document.divLoad1')
      oLoad.moveIt(page.x50-loaderWidth/2,page.y50-20)
      oLoadText.moveIt(loaderWidth/2 - oLoadText.w/2,10)
      oLoad.clipTo(0,loaderWidth,40,0,1)
      oLoad2.per = loaderWidth/numImages
    }
    function loadIt(ok){
      currentImg++
      if(oLoad2) oLoad2.clipTo(0,oLoad2.per*currentImg,40,0,1)
      if(!ok){
        oLoadCont.css.visibility='hidden'
        oLoadCont=null; oLoad1=null; oLoad2=null;
      }
    }
    function loadIt_display(ok){
      currentImg++
      if(oLoad2) oLoad2.clipTo(0,oLoad2.per*currentImg,40,0,1)
      if(currentImg<=numImages) setTimeout("loadIt_display(1)",200)
      else{
        oLoadCont.css.visibility='hidden'
        window.location="http://www.baidu.com/"
      }
    }
    </script>
    <div id="divLoadCont">
      <div id="divLoad1">
        <div id="divLoad2"></div><br>
        <div id="divLoadText">Loading...</div>
      </div>
    </div>
    <script>
    startLoading()
    //onload=loadIt; //- LEAVE THIS LINE WHILE TESTING. UNCOMMENT WHEN READY
    loadIt_display(1) //LEAVE THIS LINE WHILE TESTING. DELETE WHEN READY
    </script>