function B(sName) {
    this.name = sName;
}
B.prototype = {
    instanceCreatButtonCount: 0,funA: function () { // alert instance's name
        alert(this.name);
    },funB: function () { // create a button which clikced can alert this instance's name through funA;
        var that = this;
        B.prototype.instanceCreatButtonCount++;
        var id = "_id" + that.instanceCreatButtonCount;
        var str = "