IE6下fixed失效的解决方法

<!--[if IE 6]>
<script type="text/javascript">
(function($) {      
  jQuery.fn.Fixed = function(options) {  
    var defaults = {
      x:0,  
      y:0  
    };  
    var o = jQuery.extend(defaults, options);  
    var isIe6 = !window.XMLHttpRequest;
    var html= $(‘html‘);  
    if (isIe6 && html.css(‘backgroundAttachment‘) !== ‘fixed‘) { //防止抖动 
      html.css(‘backgroundAttachment‘,‘fixed‘)
      .css(‘backgroundImage‘,‘url(about:blank)‘);
    };
    return this.each(function() {  
      var domThis=$(this)[0];  
      var objThis=$(this);  
      if(isIe6){
        objThis.css(‘position‘ , ‘absolute‘);
        domThis.style.setExpression(‘left‘, ‘eval((document.documentElement).scrollLeft + ‘ + o.x + ‘) + "px"‘);  
        domThis.style.setExpression(‘top‘, ‘eval((document.documentElement).scrollTop + ‘ + o.y + ‘) + "px"‘); 
      } else {  
        objThis.css(‘position‘ , ‘fixed‘).css(‘top‘,o.y).css(‘left‘,o.x);  
      }
    });  
  };        
})(jQuery)
</script>
<![endif]-->

<!--[if IE 6]>
<script type="text/javascript">
$(function(){
$(‘.float‘).Fixed({x:800,y:200});
});
</script>
<![endif]-->

<!--[if IE 6]>
<script type="text/javascript">
$(function(){
//centerX和centerY是可视窗口的高和宽，需要减去自身的的宽度或高度的一半才能居中
var screenHeight=document.documentElement.clientHeight,
　　screenWidth=document.documentElement.clientWidth,
      floatHeight=$(‘.float‘).height(),
      floatWidth=$(‘.float‘).width();
    $(‘.float‘).Fixed({
        x:(screenWidth-floatWidth)/2,
        y:(screenHeight-floatHeight)/2
    });
});
</script>
<![endif]-->

<!--[if IE 6]>
<script type="text/javascript">
$(function(){
//centerX和centerY是可视窗口的高和宽，高度自定义，宽度为屏幕宽度-浮层宽度
var screenHeight=document.documentElement.clientHeight,
　　screenWidth=document.documentElement.clientWidth,
      floatHeight=$(‘.float‘).height(),
      floatWidth=$(‘.float‘).width();
    $(‘.float‘).Fixed({
        x:screenWidth-floatWidth,
        y:300
    });
});
</script>
<![endif]-->