Throwing String Exceptions : Error Exceptions : Development JAVASCRIPT DHTML TUTORIALS

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Throwing String Exceptions



<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-1]
    }
    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>