ie6下absolute:fixed问题，完美兼容

普通css代码

.fix_foot{height: 30px; background: #ff0000; position: fixed; bottom: 0px;  100%; z-index:10;}

ie6兼容代码

* html,* html body{background-image:url(about:blank);background-attachment:fixed}
* html .fix_foot{position:absolute;left:expression(eval(document.documentElement.scrollLeft));top:expression(eval(document.documentElement.scrollTop))}
* html .fix_foot{position:absolute;left:expression(eval(document.documentElement.scrollLeft+document.documentElement.clientWidth-this.offsetWidth)-(parseInt(this.currentStyle.marginLeft,10)||0)-(parseInt(this.currentStyle.marginRight,10)||0));top:expression(eval(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-(parseInt(this.currentStyle.marginTop,10)||0)-(parseInt(this.currentStyle.marginBottom,10)||0)))}

用的时候直接这样放：（而且不会出现抖动）

.fix_foot{height: 30px; background: #ff0000; position: fixed; bottom: 0px;  100%; z-index:10;}
/*IE6兼容*/
* html,* html body{background-image:url(about:blank);background-attachment:fixed}
* html .fix_foot{position:absolute;left:expression(eval(document.documentElement.scrollLeft));top:expression(eval(document.documentElement.scrollTop))}
* html .fix_foot{position:absolute;left:expression(eval(document.documentElement.scrollLeft+document.documentElement.clientWidth-this.offsetWidth)-(parseInt(this.currentStyle.marginLeft,10)||0)-(parseInt(this.currentStyle.marginRight,10)||0));top:expression(eval(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-(parseInt(this.currentStyle.marginTop,10)||0)-(parseInt(this.currentStyle.marginBottom,10)||0)))}