form-js

FormJS

This library provides a simple API to manipulate a form or its related elements with JavaScript. Supports IE10+, all modern browsers, and mobile.

It's important for you to use native form elements (i.e. <select>, <input>, etc) because they come with critical built-in logic needed for the interactions that users expect. Like tabbing to fields, pressing enter or spacebar to commit a dropdown item, mobile keyboard input triggering, etc.

Benefits

• Automatic form data binding (JSON data and JS object literals)
• Use CSS to easily customize hard-to-style native elements (i.e. dropdowns)
• Listen to user events on forms
• Easily change and update form elements and their values with JavaScript
• Trigger events programmatically

Support

• Checkboxes
• Radio Buttons
• Input Fields
• Dropdowns
• Entire forms

Usage

Styling form elements

Let's say you wanted to style a dropdown menu with the following html:

<select>
    <option value="MD">Maryland</option>
    <option value="VA" selected>Virginia</option>
    <option value="DC">Washington, DC</option>
</select>

With this library, you can do this:

var dropdown = new Dropdown({
    el: document.getElementsByTagName('select')[0]
});

Which will change your HTML into this:

<div class="dropdown-wrapper">
    <div class="dropdown-container">
        <div class="dropdown-value-container">Virginia</div>
        <div class="dropdown-option-container">
            <div class="dropdown-option" data-value="MD">Maryland</div>
            <div class="dropdown-option dropdown-option-selected" data-value="VA">Virginia</div>
            <div class="dropdown-option" data-value="DC">Washington, DC</div>
        </div>
    </div>
    <select>
        <option value="MD">Maryland</option>
        <option value="VA" selected>Virginia</option>
        <option value="DC">Washington, DC</option>
    </select>
</div>

Then you can style the dropdown using CSS (and just hide the <select> element).

Programmatically change the element's value

Each class comes with a set of utility methods so you can change the elements via JS. Using the example above, you could do the following:

// set the selected value programmatically
dropdown.setValue('DC');

// get the new data value
dropdown.getValue(); // => "DC"

// get the display value
dropdown.getDisplayValue(); // => "Washington, DC"

Listening to change events

You can also listen to events on form elements. Given the following input element...

<input type="text" value="" placeholder="Enter text here" />

You can do the following:

var inputField = new InputField({
    el: document.getElementsByTagName('input')[0],
    onChange: function (el) {
        // user has finished typing into the field!
    },
    onKeyDownChange: function (el) {
        // the user has typed a key into the field!
    }
});
// set the value
inputField.setValue('My text'); // set new value
// get the new value
inputField.getValue(); // => "My text"

Detect when user changes any value in a form

Suppose you have this HTML:

<form class="debt-info-form">
    <input type="text" name="first_name" value="" />
    <select name="loan_type">
        <option value="CC">Credit Card</option>
        <option value="Mortgage">Mortgage</option>
        <option value="HELO">HELO</option>
        <option value="Student Loan">Student Loan</option>
    </select>
</form>

You can detect when a user changes any of the form's elements like so:

var form = new Form({
    el: document.body.getElementsByClassName('debt-info-form')[0],
    onValueChange: function (val, el) {
        // a value has been changed!
       console.log('new value: ' + val);
    }
});
form.setup();

Examples

Examples can be found in the examples page.

Release History

• 2015-03-26 v1.0.0 Official release.