jquery实现拖拽调整Div大小

(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();