Code snippet pls?

Hello

I copied and pasted the below code (from Google to my_Adobe_form's Java script editor) at CHANGE event of a specific input enabled field (COUNTRY drop-down of adobe form), but,am getting an error/red ribbon on Java Script, pls. let me know the correct syntax with any any syntax errors,

if (xfa.event.newText > 999) {
xfa.event.change = "";
}

Thank you

This is NOT a Java script forum.