JS this的用法 为何实现不了移入变色

window.onload=function() 
    { 
          var oTab=document.getElementById('tab1');

          for(var i=0; i<oTab.tBodies[0].rows.length; i++)  
              { 
               oTab.tBodies[0].rows[i].onmouseover=function()
            { 
                 this.style.background='#ccc'; 
            }; 
            oTab.tBodies[0].rows[i].onmouseout=function() 
              { 
                  this.style.background='#f00'; 
            }; 
    };

};

 oTab.tBodies[0].rows[i].onmouseout=function() 
              { 
                  this.style.background=#f00; //注意引号，改this.style.background='#f00';
            }; 

http://blog.csdn.net/zhikun518/article/details/7936603