本篇文章主要是對js通過八個點 拖動改變div大小的實現方法進行了介紹，需要的朋友可以過來參考下，希望對大家有所幫助
代碼如下: <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Resize</title> <style type="text/css"> #rRightDown,#rLeftDown,#rLeftUp,#rRightUp,#rRight,#rLeft,#rUp,#rDown{ position:absolute;background:#C00;width:6px;height:6px;z-index:5;font-size:0;} #rLeftDown,#rRightUp{cursor:ne-resize;} #rRightDown,#rLeftUp{cursor:nw-resize;} #rRight,#rLeft{cursor:e-resize;} #rUp,#rDown{cursor:n-resize;} #rRightDown{ bottom:-3px; right:-3px;} #rLeftDown{ bottom:-3px; left:-3px;} #rRightUp{ top:-3px; right:-3px;} #rLeftUp{ top:-3px; left:-3px;} #rRight{ right:-3px; top:50%} #rLeft{ left:-3px; top:50%} #rUp{ top:-3px; left:50%} #rDown{ bottom:-3px; left:50%} </style> </head> <body> <div id='ss' style="height:100px; width:100px; border:1px solid #000000; position:absolute; left:200px; top:200px;" > <div id="rRightDown"> </div> <div id="rLeftDown"> </div> <div id="rRightUp"> </div> <div id="rLeftUp"> </div> <div id="rRight"> </div> <div id="rLeft"> </div> <div id="rUp"> </div> <div id="rDown"></div> </div> <script> var Sys = (function(ua){ var s = {}; s.IE = ua.match(/msie ([d.]+)/)?true:false; s.Firefox = ua.match(/firefox/([d.]+)/)?true:false; s.Chrome = ua.match(/chrome/([d.]+)/)?true:false; s.IE6 = (s.IE&&([/MSIE (d).0/i.exec(navigator.userAgent)][0][1] == 6))?true:false; s.IE7 = (s.IE&&([/MSIE (d).0/i.exec(navigator.userAgent)][0][1] == 7))?true:false; s.IE8 = (s.IE&&([/MSIE (d).0/i.exec(navigator.userAgent)][0][1] == 8))?true:false; return s; })(navigator.userAgent.toLowerCase()); var $ = function (id) { return document.getElementById(id); }; var Css = function(e,o){ for(var i in o) e.style[i] = o[i]; }; var Extend = function(destination, source) { for (var property in source) { destination[property] = source[property]; } }; var Bind = function(object, fun) { var args = Array.prototype.slice.call(arguments).slice(2); return function() { return fun.apply(object, args); } }; var BindAsEventListener = function(object, fun) { var args = Array.prototype.slice.call(arguments).slice(2); return function(event) { return fun.apply(object, [event || window.event].concat(args)); } }; var CurrentStyle = function(element){ return element.currentStyle || document.defaultView.getComputedStyle(element, null); }; function addListener(element,e,fn){ element.addEventListener?element.addEventListener(e,fn,false):element.attachEvent("on" + e,fn); }; function removeListener(element,e,fn){ element.removeEventListener?element.removeEventListener(e,fn,false):element.detachEvent("on" + e,fn) }; var Class = function(properties){ var _class = function(){return (arguments[0] !== null && this.initialize && typeof(this.initialize) == 'function') ? this.initialize.apply(this, arguments) : this;}; _class.prototype = properties; return _class; }; var Resize =new Class({ initialize : function(obj){ this.obj = obj; this.resizeelm = null; this.fun = null; //記錄觸發什麼事件的索引 this.original = []; //記錄開始狀態的數組 this.width = null; this.height = null; this.fR = BindAsEventListener(this,this.resize); this.fS = Bind(this,this.stop); }, set : function(elm,direction){ if(!elm)return; this.resizeelm = elm; addListener(this.resizeelm,'mousedown',BindAsEventListener(this, this.start, this[direction])); return this; }, start : function(e,fun){ this.fun = fun; this.original = [parseInt(CurrentStyle(this.obj).width),parseInt(CurrentStyle(this.obj).height),parseInt(CurrentStyle(thi s.obj).left),parseInt(CurrentStyle(this.obj).top)]; this.width = (this.original[2]||0) + this.original[0]; this.height = (this.original[3]||0) + this.original[1]; addListener(document,"mousemove",this.fR); addListener(document,'mouseup',this.fS); }, resize : function(e){ this.fun(e); Sys.IE?(this.resizeelm.onlosecapture=function(){this.fS()}):(this.resizeelm.onblur=function(){this.fS()}) }, stop : function(){ removeListener(document, "mousemove", this.fR); removeListener(document, "mousemove", this.fS); window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty(); }, up : function(e){ this.height>e.clientY?Css(this.obj,{top:e.clientY + "px",height:this.height-e.clientY + "px"}):this.turnDown(e); }, down : function(e){ e.clientY>this.original[3]?Css(this.obj,{top:this.original[3]+'px',height:e.clientY-this.original[3]+'px'}):this.turnUp(e); }, left : function(e){ e.clientX<this.width?Css(this.obj,{left:e.clientX +'px',width:this.width-e.clientX + "px"}):this.turnRight(e); }, right : function(e){ e.clientX>this.original[2]?Css(this.obj,{left:this.original[2]+'px',width:e.clientX-this.original[2]+"px "}):this.turnLeft(e) ; }, leftUp:function(e){ this.up(e);this.left(e); }, leftDown:function(e){ this.left(e);this.down(e); }, rightUp:function(e){ this.up(e);this.right(e); }, rightDown:function(e){ this.right(e);this.down(e); }, turnDown : function(e){ Css(this.obj,{top:this.height+'px',height:e.clientY - this.height + 'px'}); }, turnUp : function(e){ Css(this.obj,{top : e.clientY +'px',height : this.original[3] - e.clientY +'px'}); }, turnRight : function(e){ Css(this.obj,{left:this.width+'px',width:e.clientX- this.width +'px'}); }, turnLeft : function(e){ Css(this.obj,{left:e.clientX +'px',width:this.original[2]-e.clientX+'px'}); } }); window.onload = function(){ new Resize($('ss')).set($('rUp'),'up').set($('rDown'),'down').set($('rLeft'),'left').set($('rRight'),'right').set($('rLeftUp' ),'leftUp').set($('rLeftDown'),'leftDown').set($('rRightDown'),'rightDown').set($('rRightUp'),'rightUp'); } </script> </body> </html>