try
\
var   Chat_Class   =   Class.create();
Chat_Class.prototype   =   {
var a=this;
initialize:function(freePPID){
button.type   =   "button";
cell.appendChild(button);
button.onclick   =   function(){
a.sendMsg(chatNumber);//?里如何?用Chat_Class的sendMsg方法,如果用this引用,会默??button,求高手指教
}
},
sendMsg:function(chatNumber){
var   msg   =   this.getCurrentMsg(chatNumber);
FreePP.SendMessage(chatNumber,msg);
}
}