place.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

if(!dojo._hasResource["dijit._base.place"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dijit._base.place"] = true;
dojo.provide("dijit._base.place");

// ported from dojo.html.util

dijit.getViewport = function(){
	//	summary
	//	Returns the dimensions and scroll position of the viewable area of a browser window

	var _window = dojo.global;
	var _document = dojo.doc;

	// get viewport size
	var w = 0, h = 0;
	var de = _document.documentElement;
	var dew = de.clientWidth, deh = de.clientHeight;
	if(dojo.isMozilla){
		// mozilla
		// _window.innerHeight includes the height taken by the scroll bar
		// clientHeight is ideal but has DTD issues:
		// #4539: FF reverses the roles of body.clientHeight/Width and documentElement.clientHeight/Width based on the DTD!
		// check DTD to see whether body or documentElement returns the viewport dimensions using this algorithm:
		var minw, minh, maxw, maxh;
		var dbw = _document.body.clientWidth;
		if(dbw > dew){
			minw = dew;
			maxw = dbw;
		}else{
			maxw = dew;
			minw = dbw;
		}
		var dbh = _document.body.clientHeight;
		if(dbh > deh){
			minh = deh;
			maxh = dbh;
		}else{
			maxh = deh;
			minh = dbh;
		}
		w = (maxw > _window.innerWidth) ? minw : maxw;
		h = (maxh > _window.innerHeight) ? minh : maxh;
	}else if(!dojo.isOpera && _window.innerWidth){
		//in opera9, dojo.body().clientWidth should be used, instead
		//of window.innerWidth/document.documentElement.clientWidth
		//so we have to check whether it is opera
		w = _window.innerWidth;
		h = _window.innerHeight;
	}else if(dojo.isIE && de && deh){
		w = dew;
		h = deh;
	}else if(dojo.body().clientWidth){
		// IE5, Opera
		w = dojo.body().clientWidth;
		h = dojo.body().clientHeight;
	}

	// get scroll position
	var scroll = dojo._docScroll();

	return { w: w, h: h, l: scroll.x, t: scroll.y };	//	object
};

dijit.placeOnScreen = function(
	/* DomNode */	node,
	/* Object */		pos,
	/* Object */		corners,
	/* boolean? */		tryOnly){
	//	summary:
	//		Keeps 'node' in the visible area of the screen while trying to
	//		place closest to pos.x, pos.y. The input coordinates are
	//		expected to be the desired document position.
	//
	//		Set which corner(s) you want to bind to, such as
	//		
	//			placeOnScreen(node, {x: 10, y: 20}, ["TR", "BL"])
	//		
	//		The desired x/y will be treated as the topleft(TL)/topright(TR) or
	//		BottomLeft(BL)/BottomRight(BR) corner of the node. Each corner is tested
	//		and if a perfect match is found, it will be used. Otherwise, it goes through
	//		all of the specified corners, and choose the most appropriate one.
	//		
	//		NOTE: node is assumed to be absolutely or relatively positioned.

	var choices = dojo.map(corners, function(corner){ return { corner: corner, pos: pos }; });

	return dijit._place(node, choices);
}

dijit._place = function(/*DomNode*/ node, /* Array */ choices, /* Function */ layoutNode){
	// summary:
	//		Given a list of spots to put node, put it at the first spot where it fits,
	//		of if it doesn't fit anywhere then the place with the least overflow
	// choices: Array
	//		Array of elements like: {corner: 'TL', pos: {x: 10, y: 20} }
	//		Above example says to put the top-left corner of the node at (10,20)
	//	layoutNode: Function(node, aroundNodeCorner, nodeCorner)
	//		for things like tooltip, they are displayed differently (and have different dimensions)
	//		based on their orientation relative to the parent.   This adjusts the popup based on orientation.

	// get {x: 10, y: 10, w: 100, h:100} type obj representing position of
	// viewport over document
	var view = dijit.getViewport();

	// This won't work if the node is inside a <div style="position: relative">,
	// so reattach it to dojo.doc.body.   (Otherwise, the positioning will be wrong
	// and also it might get cutoff)
	if(!node.parentNode || String(node.parentNode.tagName).toLowerCase() != "body"){
		dojo.body().appendChild(node);
	}

	var best = null;
	dojo.some(choices, function(choice){
		var corner = choice.corner;
		var pos = choice.pos;

		// configure node to be displayed in given position relative to button
		// (need to do this in order to get an accurate size for the node, because
		// a tooltips size changes based on position, due to triangle)
		if(layoutNode){
			layoutNode(node, choice.aroundCorner, corner);
		}

		// get node's size
		var style = node.style;
		var oldDisplay = style.display;
		var oldVis = style.visibility;
		style.visibility = "hidden";
		style.display = "";
		var mb = dojo.marginBox(node);
		style.display = oldDisplay;
		style.visibility = oldVis;

		// coordinates and size of node with specified corner placed at pos,
		// and clipped by viewport
		var startX = (corner.charAt(1) == 'L' ? pos.x : Math.max(view.l, pos.x - mb.w)),
			startY = (corner.charAt(0) == 'T' ? pos.y : Math.max(view.t, pos.y -  mb.h)),
			endX = (corner.charAt(1) == 'L' ? Math.min(view.l + view.w, startX + mb.w) : pos.x),
			endY = (corner.charAt(0) == 'T' ? Math.min(view.t + view.h, startY + mb.h) : pos.y),
			width = endX - startX,
			height = endY - startY,
			overflow = (mb.w - width) + (mb.h - height);

		if(best == null || overflow < best.overflow){
			best = {
				corner: corner,
				aroundCorner: choice.aroundCorner,
				x: startX,
				y: startY,
				w: width,
				h: height,
				overflow: overflow
			};
		}
		return !overflow;
	});

	node.style.left = best.x + "px";
	node.style.top = best.y + "px";
	if(best.overflow && layoutNode){
		layoutNode(node, best.aroundCorner, best.corner);
	}
	return best;
}

dijit.placeOnScreenAroundElement = function(
	/* DomNode */		node,
	/* DomNode */		aroundNode,
	/* Object */		aroundCorners,
	/* Function */		layoutNode){

	//	summary
	//	Like placeOnScreen, except it accepts aroundNode instead of x,y
	//	and attempts to place node around it.  Uses margin box dimensions.
	//
	//	aroundCorners
	//		specify Which corner of aroundNode should be
	//		used to place the node => which corner(s) of node to use (see the
	//		corners parameter in dijit.placeOnScreen)
	//		e.g. {'TL': 'BL', 'BL': 'TL'}
	//
	//	layoutNode: Function(node, aroundNodeCorner, nodeCorner)
	//		for things like tooltip, they are displayed differently (and have different dimensions)
	//		based on their orientation relative to the parent.   This adjusts the popup based on orientation.


	// get coordinates of aroundNode
	aroundNode = dojo.byId(aroundNode);
	var oldDisplay = aroundNode.style.display;
	aroundNode.style.display="";
	// #3172: use the slightly tighter border box instead of marginBox
	var aroundNodeW = aroundNode.offsetWidth; //mb.w;
	var aroundNodeH = aroundNode.offsetHeight; //mb.h;
	var aroundNodePos = dojo.coords(aroundNode, true);
	aroundNode.style.display=oldDisplay;

	// Generate list of possible positions for node
	var choices = [];
	for(var nodeCorner in aroundCorners){
		choices.push( {
			aroundCorner: nodeCorner,
			corner: aroundCorners[nodeCorner],
			pos: {
				x: aroundNodePos.x + (nodeCorner.charAt(1) == 'L' ? 0 : aroundNodeW),
				y: aroundNodePos.y + (nodeCorner.charAt(0) == 'T' ? 0 : aroundNodeH)
			}
		});
	}

	return dijit._place(node, choices, layoutNode);
}

}