position.js

这是一个ajax的例子大家好好的看看就是一个鱼眼的效果

        //获取指定元素位置、大小的方法
	   	function getElementPos(elementId) 
	    {      
			var ua = navigator.userAgent.toLowerCase();     
			var isOpera = (ua.indexOf('opera') != -1);     
			var isIE = (ua.indexOf('msie') != -1 && !isOpera); 
			// not opera spoof      
			var el = document.getElementById(elementId);      
			if(el.parentNode == null || el.style.display == 'none')     
		 	{	 	         
		 	         return false;     
		 	}     
		 	var parent = null;     
			var pos = [];     
			var box;
		 	if(el.getBoundingClientRect)    
			{ //IE     
		        box = el.getBoundingClientRect(); 
		        var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop); 
		        var scrollLeft = Math.max(document.documentElement.scrollLeft, document.body.scrollLeft); 
		        return {x:box.left+ scrollLeft, y:box.top + scrollTop,w:box.right-box.left,h:box.bottom-box.top};    
		        
			}     
			else if(document.getBoxObjectFor)         
			{ // FireFox
		        box = document.getBoxObjectFor(el);                                  
		        var borderLeft = (el.style.borderLeftWidth)?parseInt(el.style.borderLeftWidth):0;
		        var borderTop = (el.style.borderTopWidth)?parseInt(el.style.borderTopWidth):0;
		        pos = [box.x - borderLeft, box.y - borderTop,box.width,box.height];     
			}     
			else     
			{ 
		   		// safari & opera
		    	pos = [el.offsetLeft,el.offsetTop,el.offsetWidth,el.offsetHeight];
		    	parent = el.offsetParent;
		    	if (parent != el) 
		    	{             
		        	while (parent) 
		        	{                 
		           		pos[0] += parent.offsetLeft;
		           		pos[1] += parent.offsetTop;
		           		parent = parent.offsetParent;             
		        	}         
				}         
				if (ua.indexOf('opera')!=-1||( ua.indexOf('safari')!=-1 && el.style.position == 'absolute' ))
				{                 
					pos[0] -= document.body.offsetLeft;                 
					pos[1] -= document.body.offsetTop;         
				}  
				return {x:pos[0]+2,y:pos[1]+2,w:pos[2],h:pos[3]};      
			}              
			if (el.parentNode) 
			{ 
				parent = el.parentNode; 
			}
			else { parent = null; } 
			while (parent && parent.tagName != 'BODY' && parent.tagName != 'HTML')
			{ // account for any scrolled ancestors         
				pos[0] -= parent.scrollLeft;         
				pos[1] -= parent.scrollTop;		       
				if (parent.parentNode) 
				{ 
					parent = parent.parentNode; 
				}          
				else 
				{ 
					parent = null; 
				}     
			}
			return {x:pos[0],y:pos[1],w:pos[2],h:pos[3]}; 
	   }