JavaScript Switch 入门实例教程
JavaScript Switch 入门实例教程
有条件的声明在JavaScript被用来执行不同的行动,根据不同的条件。
范例
switch语句
如何撰写switch语句。
<html>
<body>
<script type="text/javascript">
var d = new Date();
theDay=d.getDay();
switch (theDay)
{
case 5:
document.write("<b>Finally Friday</b>");
break;
case 6:
document.write("<b>Super Saturday</b>");
break;
case 0:
document.write("<b>Sleepy Sunday</b>");
break;
default:
document.write("<b>I'm really looking forward to this weekend!</b>");
}
</script>
<p>This JavaScript will generate a different greeting based on what day it is. Note that Sunday=0, Monday=1, Tuesday=2, etc.</p>
</body>
</html>
的JavaScript switch语句
您应该使用switch语句如果你想选择一个许多区块的代码将被处决。
语法
switch(n)
{
case 1:
execute code block 1
break;
case 2:
execute code block 2
break;
default:
code to be executed if n is
different
这是它的原理就是:首先,我们有一个单一的表达语(最常见的一个变量) ,这是评价一次。价值的表达,然后与价值观为每一个案件中的结构。如果有匹配的代码块与该案件的执行。利用休息,以防止代码从运行到下一个案件自动运行。
例如
<script type="text/javascript">
//You will receive a different greeting based
//on what day it is. Note that Sunday=0,
//Monday=1, Tuesday=2, etc.
var d=new Date();
theDay=d.getDay();
switch (theDay)
{
case 5:
document.write("Finally Friday");
break;
case 6:
document.write("Super Saturday");
break;
case 0:
document.write("Sleepy Sunday");
break;
default:
document.write("I'm looking forward to this weekend!");
}
</script>
补充:网页制作,js教程