Disable/Enable Submit Button until all forms have been filled

Question

I want my form submit button to be disabled/enabled depending on if the form is completely filled.

When the inputs are filled, the disabled button changes to enabled

Answer 1

I think this will be much simpler for beginners in JavaScript

    //The function checks if the password and confirm password match
    // Then disables the submit button for mismatch but enables if they match
            function checkPass()
            {
                //Store the password field objects into variables ...
                var pass1 = document.getElementById("register-password");
                var pass2 = document.getElementById("confirm-password");
                //Store the Confimation Message Object ...
                var message = document.getElementById('confirmMessage');
                //Set the colors we will be using ...
                var goodColor = "#66cc66";
                var badColor = "#ff6666";
                //Compare the values in the password field 
                //and the confirmation field
                if(pass1.value == pass2.value){
                    //The passwords match. 
                    //Set the color to the good color and inform
                    //the user that they have entered the correct password 
                    pass2.style.backgroundColor = goodColor;
                    message.style.color = goodColor;
                    message.innerHTML = "Passwords Match!"
 //Enables the submit button when there's no mismatch                   
                    var tabPom = document.getElementById("btnSignUp");
                    $(tabPom ).prop('disabled', false);
                }else{
                    //The passwords do not match.
                    //Set the color to the bad color and
                    //notify the user.
                    pass2.style.backgroundColor = badColor;
                    message.style.color = badColor;
                    message.innerHTML = "Passwords Do Not Match!"
 //Disables the submit button when there's mismatch       
                    var tabPom = document.getElementById("btnSignUp");
                    $(tabPom ).prop('disabled', true);
                }
            }