HTML Tag control-why does label Add the for Attribute?

Some of the materials we used to read often tell us:When using the form label Label, do not forget to add the for attribute to bind the ID attribute of the corresponding input control.~

Why?

Used to improve user experience. Generally, if your user name is followed by a <input...> tag, you can only select an input box to select your input box. If you add <lable for = ""...>, you can also select the control by clicking the problem next to the input box.It is generally used as a tag to facilitate the user experience of the mouse. Now, as a professional design, this label should be added to your page as a consideration.

Supports Browser display: safari, ie, Firefox...
Standard: HTML/XHTML