function Stack(){
this.dataStore = [];
this.top = 0;
this.pop = pop;
this.push = push;
this.peek = peek;
this.clear = clear;
this.length = length;
this.show = show;
}
function push(element){
this.dataStore[this.top++] = element;
}
function pop(){
this.dataStore[--this.top];
}
function peek(){
return this.dataStore(this.top - 1);
}
function clear(){
this.dataStore = [];
}
function length(){
return this.dataStore.length;
}
function show(){
return this.dataStore;
}
var stack = new Stack();
stack.push ( 'John Doe');
stack.push ( 'John Doe');
stack.push ( 'Wangwu');
stack.pop();
stack.push ( 'Zhao six');
alert(stack.show());
