JavaScript实现文字横向无缝滚动效果

<div id="scroll_div" class="fl"> 
  <div id="scroll_begin">
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
   恭喜793765***获得 <span class="pad_right">50元巨人点卡奖励</span>
  </div> 
  <div id="scroll_end"></div>
 </div> 

.pad_right{ padding-right:2em;}
#scroll_div {height:26px;overflow: hidden;white-space: nowrap;width:535px;margin-left:10px;}
#scroll_begin,#scroll_end {display: inline;}

//文字横向滚动
function ScrollImgLeft(){ 
 var speed=50;
  var MyMar = null;
 var scroll_begin = document.getElementById("scroll_begin"); 
 var scroll_end = document.getElementById("scroll_end"); 
 var scroll_div = document.getElementById("scroll_div"); 
 scroll_end.innerHTML=scroll_begin.innerHTML; 
 function Marquee(){ 
  if(scroll_end.offsetWidth-scroll_div.scrollLeft<=0) 
   scroll_div.scrollLeft-=scroll_begin.offsetWidth; 
  else 
   scroll_div.scrollLeft++; 
  } 
  MyMar=setInterval(Marquee,speed); 
  scroll_div.onmouseover = function(){
　　　　　　　clearInterval(MyMar);
　　　　　}
 　　　　scroll_div.onmouseout = function(){
　　　　　　　MyMar = setInterval(Marquee,speed); 　　　　
　　　　　}  
}
ScrollImgLeft();