jQuery.fn.floatdiv=function(location){ 
//ie6要隐藏纵向滚动条 
var isIE6=false; 
if($.browser.msie && $.browser.version=="6.0"){ 
$("html").css("overflow-x","auto").css("overflow-y","hidden"); 
isIE6=true; 
}; 
//$("body").css({margin:"0px",padding:"0 10px 0 10px", 
//border:"0px", 
//height:"100%", 
//overflow:"auto" 
//}); 
return this.each(function(){ 
var loc;//层的绝对定位位置 
if(location==undefined || location.constructor == String){ 
switch(location){ 
case("rightbottom")://右下角 
loc={right:"0px",bottom:"0px"}; 
break; 
case("leftbottom")://左下角 
loc={left:"0px",bottom:"0px"}; 
break; 
case("lefttop")://左上角 
loc={left:"0px",top:"0px"}; 
break; 
case("righttop")://右上角 
loc={right:"0px",top:"0px"}; 
break; 
case("middle")://居中 
var l=0;//居左 
var t=0;//居上 
var windowWidth,windowHeight;//窗口的高和宽 
//取得窗口的高和宽 
if (self.innerHeight) { 
windowWidth=self.innerWidth; 
windowHeight=self.innerHeight; 
}else if (document.documentElement&&document.documentElement.clientHeight) { 
windowWidth=document.documentElement.clientWidth; 
windowHeight=document.documentElement.clientHeight; 
} else if (document.body) { 
windowWidth=document.body.clientWidth; 
windowHeight=document.body.clientHeight; 
} 
l=windowWidth/2-$(this).width()/2; 
t=windowHeight/2-$(this).height()/2; 
loc={left:l+"px",top:t+"px"}; 
break; 
default://默认为右下角 
loc={right:"0px",bottom:"0px"}; 
break; 
} 
}else{ 
loc=location; 
} 
$(this).css("z-index","9999").css(loc).css("position","fixed"); 
if(isIE6){ 
if(loc.right!=undefined){ 
//2008-4-1修改：当自定义right位置时无效，这里加上一个判断 
//有值时就不设置，无值时要加18px已修正层位置 
if($(this).css("right")==null || $(this).css("right")==""){ 
$(this).css("right","18px"); 
} 
} 
$(this).css("position","absolute"); 
} 
}); 
};