#infocus

A super simple pure javascript to add a class to an input element's associated label element when the input element is in focus (and remove it when it loses focus). It was created so that in focus styling could be added to labels of radio buttons and checkboxes that had been stlyed to be like buttons rather than a label and a radio/checkbox (will be redundant when CSS4 comes out).

The script determines which label element is associated with which input element by using the id and for attributes of the input and label if they are set, or by going through the parent elements of the input to find a label element.

The script is pure Javascript and uses classList, querySelector, and addEventListener. The auto script uses DOMContentLoaded, The storeLabels option uses WeakMap. If you need to support older browsers, you will need to use shims/polyfills.

infocus usage

Make it just work (will find all <input>, <select> and <textarea> input elements and will the infocus class to their associated <label> elements when they are in focus):

<script src="infocus.auto.min.js"></script>

Customise:

<script src="infocus.min.js"></script>
<script>
  infocus({
    focusClass: 'focus',
    useDocListener: true
  });
</script>

The single parameter to infocus() can either be the class to add to labels when their associated input is in focus, or an Object of options:

• focusClass {String} - The class to add to labels when their associated input is in focus, default is "infocus"
• inputSelector {String} - The selector string to find inputs to add the class to, default is "input, select, textarea"
• useDocListener {Boolean} - Whether to use a single event listener on the document, or individual listeners on each input
• storeLabels {Boolean} - If true (and WeakMap is available), labels will be stored with their associated inputs