javaScript 可以改变大小的textArea (任意html对象 div也可以)

/////////////////////////////////////////////////////////////////////////
// Generic Resize by Erik Arvidsson //
// //
// You may use this script as long as this disclaimer is remained. //
// See www.dtek.chalmers.se/~d96erik/dhtml/ for mor info //
// //
// How to use this script! //
// Link the script in the HEAD and create a container (DIV, preferable //
// absolute positioned) and add the class="resizeMe" to it. //
/////////////////////////////////////////////////////////////////////////

var theobject = null; //This gets a value as soon as a resize start

function resizeObject() {
this.el = null; //pointer to the object
this.dir = ""; //type of current resize (n, s, e, w, ne, nw, se, sw)
this.grabx = null; //Some useful values
this.graby = null;
this.width = null;
this.height = null;
this.left = null;
this.top = null;
}

//Find out what kind of resize! Return a string inlcluding the directions
function getDirection(el) {
var xPos, yPos, offset, dir;
dir = "";

xPos = window.event.offsetX;
yPos = window.event.offsetY;

offset = 8; //The distance from the edge in pixels

if (yPos el.offsetHeight-offset) dir += "s";
if (xPos el.offsetWidth-offset) dir += "e";

return dir;
}

function doDown() {
var el = getReal(event.srcElement, "className", "resizeMe");

if (el == null) {
theobject = null;
return;
}

dir = getDirection(el);
if (dir == "") return;

theobject = new resizeObject();

theobject.el = el;
theobject.dir = dir;

theobject.grabx = window.event.clientX;
theobject.graby = window.event.clientY;
theobject.width = el.offsetWidth;
theobject.height = el.offsetHeight;
theobject.left = el.offsetLeft;
theobject.top = el.offsetTop;

window.event.returnValue = false;
window.event.cancelBubble = true;
}

function doUp() {
if (theobject != null) {
theobject = null;
}
}

function doMove() {
var el, xPos, yPos, str, xMin, yMin;
xMin = 8; //The smallest width possible
yMin = 8; // height

el = getReal(event.srcElement, "className", "resizeMe");

if (el.className == "resizeMe") {
str = getDirection(el);
//Fix the cursor
if (str == "") str = "default";
else str += "-resize";
el.style.cursor = str;
}

//Dragging starts here
if(theobject != null) {
if (dir.indexOf("e") != -1)
theobject.el.style.width = Math.max(xMin, theobject.width + window.event.clientX - theobject.grabx) + "px";

if (dir.indexOf("s") != -1)
theobject.el.style.height = Math.max(yMin, theobject.height + window.event.clientY - theobject.graby) + "px";

if (dir.indexOf("w") != -1) {
theobject.el.style.left = Math.min(theobject.left + window.event.clientX - theobject.grabx, theobject.left + theobject.width - xMin) + "px";
theobject.el.style.width = Math.max(xMin, theobject.width - window.event.clientX + theobject.grabx) + "px";
}
if (dir.indexOf("n") != -1) {
theobject.el.style.top = Math.min(theobject.top + window.event.clientY - theobject.graby, theobject.top + theobject.height - yMin) + "px";
theobject.el.style.height = Math.max(yMin, theobject.height - window.event.clientY + theobject.graby) + "px";
}

window.event.returnValue = false;
window.event.cancelBubble = true;
}
}

function getReal(el, type, value) {
temp = el;
while ((temp != null) && (temp.tagName != "BODY")) {
if (eval("temp." + type) == value) {
el = temp;
return el;
}
temp = temp.parentElement;
}
return el;
}

document.onmousedown = doDown;
document.onmouseup = doUp;
document.onmousemove = doMove;
请在边框处拖动鼠标