Javascript Date Validation

I have a form that has two date fields, would like to validate both of them before proceeding. Have code that works really well for one field. Have also discovered that when doing validation that it is best to use only one javascript function, not two or more (because if one passes and one fails it will proceed!!!).

I need to call a javascript function. That function has several parts to it. On pass let the valid = true, on fail alert button. So far so good.

In the form it would look like onSubmit validform(). I dont send any at this stage. But in the function itself I need to test on field and then another. Code: