One of the handy new features for <input> elements in HTML5 is the “placeholder” attribute. If you’re unfamiliar with this attribute, it allows you to pre-populate a text input with instructions which disappear when the element receives focus or there is any entry in the element.
For example, if you had a field prompting a user to enter their username, the placeholder text might be “Enter your username here.” With the introduction and support of the “placeholder” attribute, all that would be required is the use of an input tag like <input type=”text” placeholder=”Enter your username here.”/> and the browser will automatically display your text whenever there is no entry in the field and it does not have the keyboard focus.
The only problem is that older web browsers (and even those that are not-so-old, such as IE8) lack support for placeholders, so a standalone solution is required. After contemplating a couple of different fallback implementations, I decided that for my requirements, an extremely simple implementation would be best.