Inputs disabled until previous input filled in

What I want to do is, when a user lands on the form. I want the first input to be active, so the user is able to click in, select or fill it out. I want them to fill out the form step by step so I want the next input only to activate once they have filled out the current input.

I also want the submit button to be deactivated and not to be activated until all the inputs are filled out.

What's the best way of achieving this?

I have attached an image to illustrate what I'm trying to do.

回答1:

This might give you a nice starting point: Fiddle

Add a step class to each of your form elements (I do believe for this to work they need to be each other's siblings):

<form class="step-by-step">
    <!-- Start with only the first one enabled -->
    <input type="text" class="step" id="step1" />
    <input type="text" class="step" id="step2" disabled />
    <input type="text" class="step" id="step3" disabled />
    <!-- Also works with selects,
         as long as you keep track of IDs -->
    <select id="step4" class="step" disabled>
        <option value="">Choose one</option>
        <option value="volvo">Volvo</option>
        <option value="saab">Saab</option>
        <option value="mercedes">Mercedes</option>
        <option value="audi">Audi</option>
    </select>
    <select id="step5" class="step" disabled>
        <option value="">Choose one</option>
        <option value="europe">Europe</option>
        <option value="america">America</option>
    </select>
</form>

Then, use the next() function to find the next step in the form when something changes, and either disable or enable it (or all next steps, if the element was empty):

// The change event is fired when a form element loses focus
// and its value has changed since the last time we interacted with it
$('.step').change(function() {
    var next_step = $(this).next('.step');
    var all_next_steps = $(this).nextAll('.step');
    // If the element *has* a value
    if ($(this).val()) {
        // Should also perform validation here
        next_step.attr('disabled', false);
    }
    // If the element doesn't have a value
    else {
        // Clear the value of all next steps and disable
        all_next_steps.val('');
        all_next_steps.attr('disabled', true);
    }
});

For TAB functionality, the following is a quick fix, which I'm sure can be somehow integrated with the above function.

$('.step').keydown(function(event) {
    // If they pressed tab AND the input has a (valid) value
    if ($(this).val() && event.keyCode == 9) {
        $(this).next('.step').attr('disabled', false);
    }
});

回答2:

Few things to consider:

Forms can be submitted by either clicking a button with a type="submit" or by a return key.

So, in order for you to achieve the desired effect: