/**//*
** ==================================================================================================
** 类名：CLASS_MSN_MESSAGE
** 功能：提供类似MSN消息框
** 示例：
---------------------------------------------------------------------------------------------------

var MSG = new CLASS_MSN_MESSAGE("aa",200,120,"短消息提示：","您有1封消息","今天请我吃饭哈");
MSG.show();

---------------------------------------------------------------------------------------------------
** 作者：ttyp
** 邮件：ttyp@21cn.com
** 日期：2005-3-18
** ==================================================================================================
**/


/**//*
* 消息构造
*/
function CLASS_MSN_MESSAGE(id,width,height,caption,title,message,target,action){
this.id = id;
this.title = title;
this.caption= caption;
this.message= message;
this.target = target;
this.action = action;
this.width = width?width:200;
this.height = height?height:120;
this.timeout= 150;
this.speed = 20;
this.step = 1;
this.right = screen.width -1;
this.bottom = screen.height;
this.left = this.right - this.width;
this.top = this.bottom - this.height;
this.timer = 0;
this.pause = false;
this.close = false;
this.autoHide = true;
}

/**//*
* 隐藏消息方法
*/
CLASS_MSN_MESSAGE.prototype.hide = function(){
if(this.onunload()){

var offset = this.height>this.bottom-this.top?this.height:this.bottom-this.top;
var me = this;

if(this.timer>0){
window.clearInterval(me.timer);
}

var fun = function(){
if(me.pause==false||me.close){
var x = me.left;
var y = 0;
var width = me.width;
var height = 0;
if(me.offset>0){
height = me.offset;
}

y = me.bottom - height;

if(y>=me.bottom){
window.clearInterval(me.timer);
me.Pop.hide();
} else {
me.offset = me.offset - me.step;
}
me.Pop.show(x,y,width,height);
}
}

this.timer = window.setInterval(fun,this.speed)
}
}

/**//*
* 消息卸载事件，可以重写
*/
CLASS_MSN_MESSAGE.prototype.onunload = function() {
return true;
}
/**//*
* 消息命令事件，要实现自己的连接，请重写它
*
*/
CLASS_MSN_MESSAGE.prototype.oncommand = function(){
//this.close = true;
this.hide();
window.open("http://www.baidu.com");

}
/**//*
* 消息显示方法
*/
CLASS_MSN_MESSAGE.prototype.show = function(){

var oPopup = window.createPopup(); //IE5.5+

this.Pop = oPopup;

var w = this.width;
var h = this.height;

var str = "

"

oPopup.document.body.innerHTML = str;


this.offset = 0;
var me = this;

oPopup.document.body.onmouseover = function(){me.pause=true;}
oPopup.document.body.onmouseout = function(){me.pause=false;}

var fun = function(){
var x = me.left;
var y = 0;
var width = me.width;
var height = me.height;

if(me.offset>me.height){
height = me.height;
} else {
height = me.offset;
}

y = me.bottom - me.offset;
if(y<=me.top){
me.timeout--;
if(me.timeout==0){
window.clearInterval(me.timer);
if(me.autoHide){
me.hide();
}
}
} else {
me.offset = me.offset + me.step;
}
me.Pop.show(x,y,width,height);

}

this.timer = window.setInterval(fun,this.speed)



var btClose = oPopup.document.getElementById("btSysClose");

btClose.onclick = function(){
me.close = true;
me.hide();
}

var btCommand = oPopup.document.getElementById("btCommand");
btCommand.onclick = function(){
me.oncommand();
}
var ommand = oPopup.document.getElementById("ommand");
ommand.onclick = function(){
//this.close = true;
me.hide();
window.open(ommand.href);
}
}
/**//*
** 设置速度方法
**/
CLASS_MSN_MESSAGE.prototype.speed = function(s){
var t = 20;
try {
t = praseInt(s);
} catch(e){}
this.speed = t;
}
/**//*
** 设置步长方法
**/
CLASS_MSN_MESSAGE.prototype.step = function(s){
var t = 1;
try {
t = praseInt(s);
} catch(e){}
this.step = t;
}

CLASS_MSN_MESSAGE.prototype.rect = function(left,right,top,bottom){
try {
this.left = left !=null?left:this.right-this.width;
this.right = right !=null?right:this.left +this.width;
this.bottom = bottom!=null?(bottom>screen.height?screen.height:bottom):screen.height;
this.top = top !=null?top:this.bottom - this.height;
} catch(e){}
}
var MSG1 = new CLASS_MSN_MESSAGE("aa",200,120,"短消息提示：","您有1封消息","今天请我吃饭哈");
MSG1.rect(null,null,null,screen.height-50);
//MSG1.speed = 10;
//MSG1.step = 5;
//alert(MSG1.top);
MSG1.show();

//同时两个有闪烁，只能用层代替了，不过层不跨框架
//var MSG2 = new CLASS_MSN_MESSAGE("aa",200,120,"短消息提示：","您有2封消息","好的啊");
//MSG2.rect(100,null,null,screen.height);
//MSG2.show();

今天要在javascript中将一个字符串里的所有的'!@#$'，替换成','，结果发现只能替换掉一个，后来查了一下才回忆起来javascript中的replace只能替换掉第一个匹配项。

网上提供的方法主要有两种，一种为通过indexof查看是否还存在匹配项，然后写循环替换，这样也很好。

更好的方案是通过写正则表达式来解决这个问题，replace(/要匹配的字符串/g,要替换的字符串)

网上的帖子大都是互相转载的，居的例子都是一个replace(/\-/g,'!'),但是如果要匹配的字符串长度大于1,究竟怎样写呢。

其实很简单，如果需要匹配的字符串只是字母一类的，例如abcde，那就可以直接replace(/abcde/g,'!')

如果含有特殊字符，需要在特殊字符前面转义（在字符前面加上\），当然每个字符都转义也可以的。例如!@#$，就可以这样写replace(/\!\@\#\$/g,'，')