Javascript - validate form issues

I am tyring to create a button using javascript that will do the following:

There are 3 signature lines - PO, SPO, Chief.  I want the PO line hidden until the button is click and the form is completed. 

• Check to make sure the form is complete
  • All text fields
  • All radio buttons
  • Excluding SPO and Chief signature lines 
  • If the form is not complete - display an error message and what needs completed.
• If the form is complete 
  • The CHECK FORM button will disappear
  • The PO signature line will appear

I've used different lines of code so far with mixed results.  I can get parts of it work but not all of it.  Once I fix something, there's another issue.  Below is the last line of code I was trying to use.

Code is listed below - Any insight is appreciated:

var poSignatureField = this.getField("PO");

var checkFormButton = this.getField("CHECK FORM");

function validateTextFields() {

    var textFields = ["Date5_af_date", "Name", "PACTS", "Q1", "Q2", "3text", "4text", "5text", "6text", "10text", "11text", "12text"];

    for (var i = 0; i < textFields.length; i++) {

        var field = this.getField(textFields[i]);

        if (field.value === "" && field.name !== "SPO" && field.name !== "Chief") {

            return false;

        }

    }

    return true;

}

function validateRadioButtons() {

    var radioButtons = ["Q3", "Q4", "Q6", "Q7", "Q8", "Q9", "Q10"];

    for (var i = 0; i < radioButtons.length; i++) {

        var radioButton = this.getField(radioButtons[i]);

        if (!radioButton.value) {

            return false;

        }

    }

    return true;

}

function checkFormButtonClick() {

    if (validateTextFields() && validateRadioButtons()) {

        checkFormButton.display = display.hidden;

        poSignatureField.display = display.visible;

    } else {

        app.alert("Please complete all required fields before submitting the form.");

    }

}

checkFormButton.setAction("MouseUp", checkFormButtonClick);