InfoPath Dev

Hello! I have a form that enables the user to order something and then specify quantity from a drop-down list. I would like to create a script to ensure that for every item the user chooses, there is a chosen quantity associated with it. I thought I would put it on my Submit button. Is this a correct way to do this? Also, I have never scripted in MSE before. If someone could direct me to a sample script fot this it would be great! Thanks for your help!

~If you don't have time to do it right the first time, when will you have time to fix it?~

Instead of writing a script, in your data source taskpane >> double click on the field >> check the cannot be blank checkbox. When you try to submit or save the InfoPath form, it will require that your quantity be set. No script required :-) A red star will be displayed in the quantity field until the user enters a value.