1、
<script>
var color="blue";
function a(){
//var color="blue"
if(color=="blue"){
color="red";
} else{color="blue"};
}
a();
alert(color);
</script>
<script>
function sayhi(){
alert("dsvs")
}
</script>
2、
<title>switch判断</title>
<script type="text/javascript">
var cc=prompt("请输入喜欢的吃的水果！","")
if(cc=="苹果"){
alert(cc+"不错哦！")
}
if(cc=="香蕉"){
alert(cc+"不错哦！")
}
if(cc=="橘子"){
alert(cc+"不错哦！")
}
</script>
<script>
var x=2;
switch (x){
case 1:
alert("ok!")
break;
case 2:
alert("ok2!")
break;
case 3:
alert("ok3!")
break;
default:
alert("hello!")
};
</script>
3、
<style>
div{ width:100px; height:100px; float:left; background:#CCC; border:1px #666666 solid; margin:0 10px 10px 0;}
</style>
<script>
window.onload=function(){
var but1=document.getElementsByTagName('button')[0];
var box=document.getElementById('box');
but1.onclick=function(){
alert(box.innerHTML)
};
var but2=document.getElementsByTagName('button')[1];;
but2.onclick=function(){
box.innerHTML="<h1>ok</h1>"
};
};
</script>
</head>
<body>
<button>修改内容</button>
<button>显示内容</button>
<div id="box"><ul><li>ok</li></ul></div>
4、
<script>
var ok;
var cc=null;
//alert(typeof ok) //undefing
//alert(typeof cc) //object
for(var i=0;i<10;i++){
document.write(i+'<br/>')
}
</script>