3. color: HTML5 A control for specifying a color. Description. This control looks like a text field but allows only floating-point numbers, and usually provides buttons in the form of a spinner to increase and decrease the value of the control. Therefore, they are used to pick a number whose precise value is not necessarily important. Any other content causes the browser to display an error when the form is submitted. Default range is 0 to 100. autofocus It is a helpful aid to guide users to fill out a form accurately, and it can save time: it is useful to know that your data is not correct immediately, rather than having to wait for a round trip to the server. Figure 4.5.