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The throw statement allows you to create an
exception.
The Throw Statement
The throw statement allows you to create an exception. If you
use this statement together with the try...catch statement, you
can control program flow and generate accurate error messages.
Syntax
The exception can be a string, integer, Boolean or an object.
Note that throw is written in lowercase letters. Using
uppercase letters will generate a JavaScript error!
Example 1
The example below determines the value of a variable called
x. If the value of x is higher than 10 or lower than 0 we are
going to throw an error. The error is then caught by the catch
argument and the proper error message is displayed:
<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"
}
catch(er)
{
if(er=="Err1")
alert("Error! The value is too high")
if(er == "Err2")
alert("Error! The value is too low")
}
</script>
</body>
</html>
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