模拟Flash放大镜的动态JS效果

无意看到一个FLASH,就是一个类似放大镜逐个浏览文字的效果，于是便想用js表示出来，比较简单，但是效果不是很好，好像有些BUG!继续努力中。。。

<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >
< html >
   < head >
   < meta  http-equiv ="content-type"  content ="text/html; charset=windows-1250" >
   < meta  name ="generator"  content ="PSPad editor, www.pspad.com" >
   < title ></ title >
   < style  type ="text/css" >
  html,body { font-size : 26px ; letter-spacing : 4px ; font-family : 'Arial black' }
   </ style >
   < script  type ="text/javascript" >
   var  str1 = " Tianfeng Fine Chemicals Co.Ltd "
   var  i = 0 ;
   function  animate(){
    i ++ ;
     var  s1 = document.getElementById( " s1 " );
     var  len_s = str1.length;
     if (i > len_s - 3 ){i = 0 }
    str2 = str1.substring( 0 ,i) + " <span style='font-size:30px;position:relative'> " + str1.substr(i, 1 ) + " </span> " + " <span style='font-size:34px;position:relative'> " + str1.substr(i + 1 , 1 ) + " </span> " + " <span style='font-size:30px;position:relative'> " + str1.substr(i + 2 , 1 ) + " </span> " + str1.substring(i + 3 ,len_s);
    s1.innerHTML = str2;
    setTimeout( " animate() " , 100 );
  }
   </ script >
   </ head >
   < body  onload ="animate()" >
   < div  id ="s1"   ></ div >
   </ body >
</ html >