拖拽调整Div大小

今天写了一天这个jquery插件：

可以实现对div进行拖拽来调整大小的功能。

 (function ($) {
     $.fn.dragDivResize = function () {
         var deltaX, deltaY, _startX, _startY;
         var resizeW, resizeH;
         var size = 20;
         var minSize = 10;
         var scroll = getScrollOffsets();
         var _this = this;

         for (var i = 0; i < _this.length; i++) {
             var target = this[i];
             $(target).on("mouseover mousemove", overHandler);
         }
         function outHandler() {
             for (var i = 0; i < _this.length; i++) {
                 target.style.outline = "none";
             }
             document.body.style.cursor = "default";
         }

         function overHandler(event) {
             target = event.target || event.srcElement;
             var startX = event.clientX + scroll.x;
             var startY = event.clientY + scroll.y;
             var w = $(target).width();
             var h = $(target).height();
             _startX = parseInt(startX);
             _startY = parseInt(startY);
             if ((0 < target.offsetLeft + w - _startX && target.offsetLeft + w - _startX < size) || (0 < target.offsetTop + h - _startY && target.offsetTop + h - _startY < size)) {
                 target.style.outline = "2px dashed #333";
                 if ((0 > target.offsetLeft + w - _startX || target.offsetLeft + w - _startX > size) && 0 < target.offsetTop + h - _startY && target.offsetTop + h - _startY < size) {
                     resizeW = false;
                     resizeH = true;
                     document.body.style.cursor = "s-resize";
                 }
                 if (0 < target.offsetLeft + w - _startX && target.offsetLeft + w - _startX < size && (0 > target.offsetTop + h - _startY || target.offsetTop + h - _startY > size)) {
                     resizeW = true;
                     resizeH = false;
                     document.body.style.cursor = "w-resize";
                 }
                 if (0 < target.offsetLeft + w - _startX && target.offsetLeft + w - _startX < size && 0 < target.offsetTop + h - _startY && target.offsetTop + h - _startY < size) {
                     resizeW = true;
                     resizeH = true;
                     document.body.style.cursor = "se-resize";
                 }
                 $(target).on('mousedown', downHandler);
             } else {
                 resizeW = false;
                 resizeH = false;
                 $(target).off('mousedown', downHandler);
             }
         }

         function downHandler(event) {
             target = event.target || event.srcElement;
             var startX = event.clientX + scroll.x;
             var startY = event.clientY + scroll.y;
             _startX = parseInt(startX);
             _startY = parseInt(startY);
             if (document.addEventListener) {
                 document.addEventListener("mousemove", moveHandler, true);
                 document.addEventListener("mouseup", upHandler, true);
             } else if (document.attachEvent) {
                 target.setCapture();
                 target.attachEvent("onlosecapeture", upHandler);
                 target.attachEvent("onmouseup", upHandler);
                 target.attachEvent("onmousemove", moveHandler);
             }
             if (event.stopPropagation) {
                 event.stopPropagation();
             } else {
                 event.cancelBubble = true;
             }
             if (event.preventDefault) {
                 event.preventDefault();
             } else {
                 event.returnValue = false;
             }
         }

         function moveHandler(e) {
             if (!e) e = window.event;
             var w, h;
             var startX = parseInt(e.clientX + scroll.x);
             var startY = parseInt(e.clientY + scroll.y);
             target = target || e.target || e.srcElement;
             if (target == document.body) {
                 return;
             }
             if (resizeW) {
                 deltaX = startX - _startX;
                 w = $(target).width() + deltaX < minSize ? minSize : $(target).width() + deltaX;
                 target.style.width = w + "px";
                 _startX = startX;
             }
             if (resizeH) {
                 deltaY = startY - _startY;
                 h = $(target).height() + deltaY < minSize ? minSize : $(target).height() + deltaY;
                 target.style.height = h + "px";
                 _startY = startY;
             }
             if (e.stopPropagation) {
                 e.stopPropagation();
             } else {
                 e.cancelBubble = true;
             }
         }

         function upHandler(e) {
             if (!e) {
                 e = window.event;
             }
             resizeW = false;
             resizeH = false;
             target = e.target || e.srcElement;
             $(target).on("mouseout", outHandler);
             if (document.removeEventListener) {
                 document.removeEventListener("mousemove", moveHandler, true);
                 document.removeEventListener("mouseup", upHandler, true);
             } else if (document.detachEvent) {
                 target.detachEvent("onlosecapeture", upHandler);
                 target.detachEvent("onmouseup", upHandler);
                 target.detachEvent("onmousemove", moveHandler);
                 target.releaseCapture();
             }
             if (e.stopPropagation) {
                 e.stopPropagation();
             } else {
                 e.cancelBubble = true;
             }
         }

         function getScrollOffsets(w) {
             w = w || window;
             if (w.pageXOffset != null) {
                 return { x: w.pageXOffset, y: w.pageYOffset };
             }
             var d = w.document;
             if (document.compatMode == "CSS1Compat") {
                 return { x: d.documentElement.scrollLeft, y: d.documentElement.scrollTop };
             }
             return { x: d.body.scrollLeft, y: d.body.scrollTop };
         }
     }
 }(jQuery));

 jQuery("div").dragDivResize();

记录一下今天的劳动成果，可能会有很多不成熟的地方，欢迎大家来指正，谢谢！