id and class selectors
If you want to set CSS styles in HTML elements, you need to set "id" and "class" in the element Selector.
id selector
The id selector can specify a specific style for HTML elements marked with a specific id.
The HTML element uses the id attribute to set the id selector, and the id selector in CSS is defined with "#".
The following style rules apply to the element attribute id="para1":
Example
#para1 { text-align:center; color:red; }
The ID attribute should not start with a number. IDs starting with a number are browsed in Mozilla/Firefox does not work in the device.
class selector
class selector is used to describe the style of a group of elements. The class selector is different from the id selector. Class can be used in multiple elements.
The class selector is represented by the class attribute in HTML. In CSS, the class selector is displayed with a dot ".":
In the following example, all objects with the center class HTML elements are all centered.
p.center {text-align:center;}
The first character of the class name cannot use numbers! It won't work in Mozilla or Firefox.
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