例子如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/htmlcharset=utf-8" />
<title>无标题文档</title>
</head>
<body>
<script type="text/javascript">
document.onkeydown = checkdelete
function checkdelete(e)
{
var e = window.event || e
var code = e.which || e.keyCode
if(code == 46)
{
alert("您按了删除键")
}
}
</script>
</body>
</html>
<!doctype html><html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
*{margin:0padding: 0}
#div_id p{width:80pxheight:30pxtext-align: leftborder: 1px solid #000line-height: 30px}
#div_id p button{float:rightheight:30px}
</style>
<script src = "js/tool.js"></script>
<script>
window.onload = function(){
var div = document.getElementById("div_id")
var button = document.getElementsByTagName("button")
for(var i = 0 i < button.length - 1 i++){
button[i].onclick = function(){
alert("加入购物车成功")
var p = document.createElement("p")
var pContent = document.createTextNode(this.innerHTML)
p.appendChild(pContent)
div.appendChild(p)
var delBtn = document.createElement("button")
var delBtnContent = document.createTextNode("x")
delBtn.appendChild(delBtnContent)
p.appendChild(delBtn)
delBtn.onclick = function(){
div.removeChild(p)
}
//setCookie("购物",div.innerHTML,getDate(100))
}
}
var isTrue = false
var button1 = document.getElementById("button_id")
button1.onclick = function(){
if(isTrue == false){
button1.innerHTML ="隐藏购物车"
isTrue = true
/*if(getCookie("购物") != undefined){
div.innerHTML = getCookie("购物")
}*/
div.style.display = "block"
}else if(isTrue){
button1.innerHTML ="显示购物车"
isTrue = false
div.style.display = "none"
/*if(getCookie("购物") != undefined){
div.innerHTML = getCookie("购物")
div.style.display = "none"
}*/
}
}
}
</script>
</head>
<body>
<button>商品1</button>
<button>商品2</button>
<button>商品3</button>
<button>商品4</button>
<button>商品5</button><br/><br/>
<button id = "button_id">显示购物车</button>
<div id = "div_id" style="display:none"></div>
</body>
</html>
js没有字典这个数据类型，js的对象都是键值对的，判断对象有没有key很简单，如： var person = { name: 'zero'}// 判断person里面有没有name这个键，可以这样var key = 'name'alert(!!person[key])
