In the forum, I saw netizen jeanjean20 mentioning how Marquee can be modified to meet the standards. I looked at my friends’ comments and thought they were all very good. Moderator greengnn pointed out that Marquee does not meet the standards and has been abandoned by W3C. Some friends were very aggrieved and said that it was unreasonable to go. The effect that was good at first has now disappeared. Some friends also said it was good to go, but it was annoying to watch. Everyone has their own perspective of understanding, but how we understand it is one thing, but we need to figure out why. Here I will modify and add some content to greengnn’s conclusion. I hope everyone understands and can figure it out.
The first thing to correct is: Marquee was abandoned by W3C. This sentence is actually wrong. Why? Because Marquee has never been used as an official label by W3C. W3C has never formulated this label, let alone "abandoned" it. This is like saying divorce before you are married. In fact, Marquee, like many other labels, is privately produced by companies such as Microsoft and Netscape, and the W3C has not recognized this label. This rich company has a problem with being unreasonable, but this unprofitable organization is just a tough talker!
Why doesn’t W3C recognize Marquee? It should be said that this label is regarded as a screwdriver in the eyes of most web designers! In the early years, we still used technological power as capital to show off. But now it is no longer recommended to use it (here is a digression: many people say that W3C does not allow it to be used. This is wrong. W3C has no right to restrict you from using it or not being able to use it.), why? Then we need to clarify what this standard is. . A standard is not a technology, it is just a specification and proposal. We still use the original tags in HTML4.0. The standard does not add any tags to our XHTML, but gives the recommended ones (for example: p, div, ul, dl, span, em... ), which ones are advocated not to be used (for example: font, b, u, i...), and it is advocated that semantics and usage standards be required. Of course, the standard is not just XHTML, but also includes CSS, DOM and scripting languages. Many people think that CSS was created after standards. In fact, it is not true. CSS has been around for a long time. Standards are the same for CSS. It is recommended not to use some CSS developed by some browser manufacturers, such as CSS filters.
There is another very important point in the standard, which is functional separation. It is divided into three parts: structure, style, and behavior. These three parts include structure (xHTML, XML), sample (CSS), and behavior (DOM, ECMAScript) respectively. At this point, let’s go back and think about why Marquee is not recognized by W3C. I think everyone should understand. Like FONT, B and other tags, it is no longer a structural tag. They have style and behavioral characteristics, and it is obviously redundant to classify them in the category of structure.
So, if you want the effect of Marquee to be retained or realized, you need to pay more attention to JavaScript. The scripting language will definitely make your web page move. If you want to make the place you specify move, of course you must pay attention to the use of ID and CLASS in the tag.
In order to make it easier for everyone to use this interesting effect, I specially asked Aoao to write a piece of JS. See the following code:
JS code:
function getElementsByClass(searchClass,tagName) {
var classElements = new Array();
if ( tagName == null )
tagName = '*';
var els = document.getElementsByTagName(tagName);
var elsLen = els.length;
var pattern = new RegExp("( ^|s)" searchClass "(s|$)");
for (i = 0, j = 0; i < elsLen; i ) {
if ( pattern.test(els[i]. className) ) {
classElements[j] = els[i];
j ;
}
}
return classElements;
}
function ccMarquee(className){
var a=getElementsByClass(className);
for (i = 0; i < a.length; i ) {
a[i].innerHTML="";
}
}window.onload = function () {
ccMarquee("ccMarquee");
}
XHTML code :
Please pay attention , where you need to use the scrolling effect, just add Class="ccMarquee" to any peripheral label. Pay attention to capitalization.
Attachment:
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
