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Validating Numeric Values
Users
can type almost anything into a form, so you'll make sure that
fields like zip code contain only numbers.
<HTML>
<HEAD>
<TITLE>How Many Times Have You Been Before Here
?</TITLE>
<SCRIPT LANGUAGE=JAVASCRIPT>
function isNum(passedVal)
{
if(passedVal =="")
{
return false
}
for(i=0;i<passedVal.length;i++)
{
if(passedVal.charAt(i)<"0")
{
return false
}
if(passedVal.charAt(i)>"9")
{
return false
}
}
return true
}
function validZip(inZip)
{
if(inZip =="")
{
return true
}
if(isNum(inZip))
{
return true
}
return false
}
function submitIt(form)
{
if(!validZip(form.zip.value))
{
alert("This is an invalid zip code")
form.zip.focus()
form.zip.select()
return false
}
return
true
}
</SCRIPT>
</BODY>
</HTML>
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