How to validate PDF form?

I have a writeable PDF form made in Acrobat Professional. I want to validate that a numerical entry is in a certain range [a,b]. If it is not, I want an alert to pop up with the message, "Please contact Larry at XXX-XXX-XXXX to get your form processed." Can someone write up a quick snippet of code that does this for a PDF? I know how to do it for a web form.

You could do something like this:

if (event.value > 3 && event.value < 10) {
    event.rc = false;
    app.alert({
        cMsg: "Please contact Larry at xxx to process your form.",
        cTitle: "My Window Title",
        nIcon: 0,
        nType: 1
    });
}

You can enter this validation script by editing the properties of a field. Go to "Validate Tab", click "Run custom validation script", then "Edit...". Type the code into the JavaScript Editor window, and then click "Ok" and "Close".

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