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/*
JavaScript Bible, Fourth Edition
by Danny Goodman
John Wiley & Sons CopyRight 2001
*/
<HTML>
<HEAD>
<TITLE>Throwing a String Exception</TITLE>
<SCRIPT LANGUAGE="JavaScript">
var letters = new Array("A","B","C","D","E")
function getLetter(fld) {
try {
var inp = parseInt(fld.value, 10)
if (isNaN(inp)) {
throw "Entry was not a number."
}
if (inp < 1 || inp > 5) {
throw "Enter only 1 through 5."
}
fld.form.output.value = letters[inp]
}
catch (e) {
alert(e)
fld.form.output.value = ""
fld.focus()
fld.select()
}
}
</SCRIPT>
</HEAD>
<BODY>
<H1>Throwing a String Exception</H1>
<HR>
<FORM>
Enter a number from 1 to 5:
<INPUT TYPE="text" NAME="input" SIZE=5>
<INPUT TYPE="button" VALUE="Get Letter" onClick=getLetter(this.form.input)>
Matching Letter is:<INPUT TYPE="text" NAME="output" SIZE=5>
</FORM>
</BODY>
</HTML>
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