Javascript Tooltip clearing issue

I ended up uninstalling acrobat to make sure it is now any settings/preferences that could trigger this hiccup, did that and redid the script and it worked. Thank you to everybody

It is a good practice to include the "object" of the property or method you are trying to access or modify. All the properties and methods you are trying to use refer to the current opened and focused PDF, so I would add the "this." for the object;

Have you tried to add any debugging statements to print out the item being processed?

// Set all field tooltips to blank
console.show();console.clear();
console.println("number of fields: " + this.numFields);
for (var i = 0; i < numFields; i++) {
console.println(i + ": " + this.getNthFieldName(i) + " " + this.getField(this.getNthFieldName(i)).userName);
getField(getNthFieldName(i)).userName = "";
}

Works fine for me. Are you sure you're selecting the whole code when you're executing it?