一 页面输出
1.头部文件
<head>
<script language="javascript">
document.write("脚本之家www.jb51.net");
</script>
</head>
2.页面内
<body>
<script>
document.write("脚本之家");
</script>
</body>
3.外部文件
<script src="display.js"></script>
4.利用页面ID的innerHtml
<script>
window.onload = writeMessage; // 页面加载时调用writeMessage函数
writeMessage() {
document.getElementById("helloMessage").innerHTML = "脚本之家";
//找到dom ID（helloMessage），修改其html内容
}
</script>
5.警告
alert("广州百汇物流有限公司");
6.询问
if (confirm("是否访问我们的首页"))
{
alert("是的，前往");
}
else {
alert("退出");
}
7.输入
var ans = prompt("输入你的留言","您好，");
if (ans) {
alert("你说:" + ans);
}
else {
alert("退出，没有留言");
}
8.页面跳转
<script>
window.onload = initAll;
function initAll() {
document.getElementById("redirect").onclick = initRedirect;
}
function initRedirect()
{
window.location = "index.html";
return false;
}
</script>
<a href="https://www.jb51.net" id="redirect">脚本之家</a>
9.判断分支
<script>
window.onload = initAll;
function initAll() {
document.getElementById("Lincoln").onclick = saySomething;
document.getElementById("Kennedy").onclick = saySomething;
document.getElementById("Nixon").onclick = saySomething;
}
function saySomething() {
switch(this.id) {
case "Lincoln":
alert("Four score and seven years ago...");
break;
case "Kennedy":
alert("Ask not what your country can do for you...");
break;
case "Nixon":
alert("I am not a crook!");
break;
default:
}
}
</script>
<form action="#">
<input type="button" id="Lincoln" value="Lincoln" />
<input
type="button" id="Kennedy" value="Kennedy" />
<input type="button" id="Nixon"
value="Nixon" />
</form>
10.异常捕获
window.onload = initAll;
function initAll() {
var ans = prompt("输入参数：","");
try {
if (!ans || isNaN(ans) || ans<0) {
throw new Error("输入为非数");
}
alert("根号" + ans + " 是 " + Math.sqrt(ans));
}
catch (errMsg) {
alert(errMsg.message);
}
}