Explanation of background:transparent in css

This article mainly introduces the explanation about background:transparent in css. It has certain reference value. Now I share it with you. Friends in need can refer to

What is transparent in css? What does it mean? I have always thought it was strange. What is it used for? This article will explain it in detail. Friends who need it can refer to it

Sometimes when I look at css, I see that some css attributes are defined as background:transparent . It means the background is transparent. In fact, the default color of the background is the transparent attribute. So it’s the same whether you write or not.
I haven’t written an article for a while. I have been in school. Although I have a computer with me, I can’t access the Internet! Recently I am using JavaScript to write a web version of the operating system. Once it is written, it will definitely Posting this, I encountered many problems during the writing process. Many of them are details and very troublesome. However, I have been working hard to solve them. It is also a kind of improvement for myself. Now let me talk about a problem I encountered recently. .
As everyone knows, you use createelement to create a new p. By default, the backgroundcolor attribute in the style of this p is transparent. Haha, if I make a mask of p, then please see the following code:

p.style.position="absolute"; 
p.style.width=document.body.clientWidth+"px"; 
p.style.height=document.body.clientHeight+"px"; 
p.style.left="0px"; 
p.style.top="0px"; 
p.style.zIndex="2000"; 
p.style.backgroundColor="black"; 
p.style.filter="alpha(opacity="+0+");";

This is a lot of settings for mask p, which means that users are shielded from operating other elements on the web page.
We mainly look at the last two lines of code. As I said before, the default of p The backgroundcolor attribute is transparent, that is, transparent, so why do we need to go to the trouble of setting a black (it doesn't matter, just set a color as long as it is not transparent, and it cannot be an empty string. The browser will default to an empty string See it as transparent), and set the filter to make it transparent.
I did the experiment myself. I was confused about the test results at first, but when I calmed down and thought about it, I discovered the difference. If we didn’t have the above In the last two sentences of the code, we can operate on the masked elements, which means that it will not have a shielding effect, but this operation is limited. Specifically, we can only operate on the focused elements. , such as text, pictures, buttons, etc., let me give you an example:

<p style="border:1px red solid;width:100px;height:100px" onclick="alert(1)">123</p>

Under normal circumstances, as long as you click anywhere on this p, it will alert, but when it is covered by an element with a background color of transparent When we click 123, the alert will occur, because the text can gain focus, and the same goes for other elements. By the way, the event of the element whose background color is transparent will be intercepted by the element covered by it. If The object we trigger does not have focus, then the event will be exchanged to the transparent element for processing and bubbled according to this element. Otherwise, the event with focus will be processed by the object with focus, without exchange, and according to the element with focus. Perform bubbling. (It doesn’t seem to be very easy to understand. You can understand it by doing more experiments.)
Let’s put it this way, everyone understands. This is why the last two sentences are needed. Only in this way can we perform bubbling on web page elements. Completely shielded.
Set the style to transparent color
Sometimes, if the above text says

background:inherit;

, then the following text may need to clear the background, so it writes

background:transparent;

with a transparent background. Just remove the
If an element covers another element, and you want to display the following element, then you need to set the background of the above element to transparent
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