- switch 可以省略default的break
var day=new Date().getDay();
switch (day)
{
case 6:
x="Today it's Saturday";
break;
case 0:
x="Today it's Sunday";
break;
default:
x="Looking forward to the Weekend";
}
- 循环分为以下几种
for
for (var i=0; i<5; i++)
{
x=x + "The number is " + i + "<br>";
}
可以省略初赋值
var i=2,len=cars.length;
for (; i<len; i++)
{
document.write(cars[i] + "<br>");
}
遍历对象
var person={fname:"John",lname:"Doe",age:25};
for (x in person)
{
txt=txt + person[x];
}
- break 搭配标签引用可以跳出任何JS代码块
cars=["BMW","Volvo","Saab","Ford"];
list:
{
document.write(cars[0] + "<br>");
document.write(cars[1] + "<br>");
document.write(cars[2] + "<br>");
break list;
document.write(cars[3] + "<br>");
document.write(cars[4] + "<br>");
document.write(cars[5] + "<br>");
}
- try-catch-throw
<!DOCTYPE html>
<html>
<body>
<script>
function myFunction()
{
try
{
var x=document.getElementById("demo").value;
if(x=="") throw "值为空";
if(isNaN(x)) throw "不是数字";
if(x>10) throw "太大";
if(x<5) throw "太小";
alert(x);
}
catch(err)
{
var y=document.getElementById("mess");
y.innerHTML="错误：" + err + "。";
}
}
</script>
<h1>我的第一个 JavaScript 程序</h1>
<p>请输入 5 到 10 之间的数字：</p>
<input id="demo" type="text">
<button type="button" onclick="myFunction()">测试输入值</button>
<p id="mess"></p>
</body>
</html>
