JavaScript: Reading and setting style attributes of document elements _ javascript skills

Sometimes we need to use js to set the style attributes of the document. The following describes some methods and principles for analysis. You can see that it is okay. First, let's talk about the style sheet attributes.
1. inline style is set in the element style attribute, with the highest level
2. Page Style table definition is page Level 2
3. External link style table File
JavaScript gets and sets the css attributes of document elements:
1. Get the Style attribute set in the element Style attribute,
Document. getElementById (id). style. height;
If yes, the property value is returned. If no value is returned, null is returned.
Both IE and Firefox are available, but some attribute values may return different values. For example, Firefox returns rgb, While IE returns hexadecimal numbers.
Test code: