JavaScript学习与实践(15)
throw语句语序你创建一个例外
例子:
<html>
<body>
<script type="text/javascript">
var x=prompt("Enter a number between 0 and 10:","")
try
{
if(x>10)
throw "Err1"
else if(x<0)
throw "Err2"
else if(isNaN(x))
throw "Err3"
}
catch(er)
{
if(er=="Err1")
alert("Error! The value is too high")
if(er == "Err2")
alert("Error! The value is too low")
if(er == "Err3")
alert("Error! The value is not a number")
}
</script>
</body>
</html>
如果你用try...catch,throw语句可以给你创建一个例外,用来指定确定错误的消息
语法:
throw(exception)
这个exception可以是一个字符串,或者一个整形,或者是一个布尔或者是一个对象