js通过八个点 拖动改变div大小的实现方法

  

复制代码 代码如下:

  <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; //记录触发什么事件的索引

  this.original = []; //记录开始状态的数组

  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(this.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>