Development web front face questions (with answers) -2

1, label what label, what role? And the role of property for use?

Tags for input element defined label (tag).
The label element does not present any special effects to the user. However, it improved the availability for mouse users. If you click on the text within the label element, it will trigger this control. That is, when the user selects the tag, the browser will automatically focus to the label and the associated form controls.
Tag should be the same for attribute id attribute related elements.
Click on one of markup, you can trigger related controls (click on the radio button you can choose Male)
<label for="male">Male</label> <input type="radio" name="sex" id="male" />
Male

2. What are the new features css3

1) transition effects

transition: css property, it takes time effect curve (the default is EASE), the time delay (default 0)