可以实现对div进行拖拽来调整大小的功能。

代码如下:
(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！