Browser conditional comment theory, use the following example to explain this problem
(X)HTML
The following code is to test the effect of conditional comment statements under Microsoft's IE browser

Copy codeThe code is as follows:

The following code is run under non-IE browsers Conditional comments

Copy codeThe code is as follows:

You are not using Internet Explorer

p>

Finally works in non-IE and special IE browsers
(or use lte lt or gt gte to judge, such as ：

).

You are using Internet Explorer version 6 h1>

From: http://www.cssplay.co.uk/menu/conditional.html
Preview model
The conditional annotation mentioned above is to determine the browser type and then define what browser What is shown below.
This dropmenu (drop-down menu) model comes from cssplay and was made after many studies and repeated tests by the author. I want to use this model to practice the principle of conditional annotation.
Let’s look at the simplest model first