JS笔记-004-常用运算符

• 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 + "
";
  }

可以省略初赋值

var i=2,len=cars.length;
for (; i");
}

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] + "
");
document.write(cars[1] + "
");
document.write(cars[2] + "
");
break list;
document.write(cars[3] + "
");
document.write(cars[4] + "
");
document.write(cars[5] + "
");
}

• try-catch-throw

我的第一个 JavaScript 程序
请输入 5 到 10 之间的数字：

测试输入值