javascript return to top effect (self-written code)_javascript skills

Nowadays, many websites use the effect of returning to the top. Of course, if you are lazy, you can also directly link a link to #, which can also achieve the effect. I took the time to write one using native javascript today. Due to my limited skills, please point out any questions.
html code:

Copy code The code is as follows:

"Notepad" is A basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Notepad is a basic text editor for creating simple documents. Notepad is most commonly used to view or edit text (.txt) files, but many users find Notepad to be a simple tool for creating web pages.

Because Notepad only supports very basic formats, you can't occasionally save special formatting in documents that need to remain plain text. It is particularly useful when creating HTML documents for web pages, because special characters or other formatting cannot be displayed on published web pages or may cause errors.

Notepad files can be saved as Unicode, ANSI, UTF-8, or big-endian Unicode format. These formats provide you with greater flexibility when working with documents in different character sets.

Back to top

toTop.js code :

Copy code The code is as follows:

//The first parameter is the button id; the second parameter Is a Boolean value, true means the button is always displayed, false means the button is displayed when the scroll distance is not 0
function toTop(id,show){
var oTop = document.getElementById(id);
var bShow = show;
if(!bShow){
oTop.style.display = 'none';
setTimeout(btnShow,50);
}
oTop.onclick = scrollToTop;
function scrollToTop(){
var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
var iSpeed ​​= Math.floor(-scrollTop/2);
if(scrollTop < ;= 0){
if(!bShow){
oTop.style.display = 'none';
}
return;
}
document.documentElement.scrollTop = document .body.scrollTop = scrollTop iSpeed;
setTimeout(arguments.callee,50);
}
function btnShow(){
var scrollTop = document.documentElement.scrollTop || document.body.scrollTop ;
if(scrollTop oTop.style.display = 'none';
}else{
oTop.style.display = 'block';
}
setTimeout(arguments.callee,50);
}
}

Note:
position:fixed is invalid under ie6, please click for compatibility details Various browser bugs. In addition, I previously wrote an article css to solve the problem of position:fixed failure in IE6 , but this effect is not supported.
PS: These are some effects I wrote casually based on my knowledge of javascript when I was bored.

Second method :
Many web pages will place a "return to top" button at the bottom, especially web pages without navigation at the bottom of the page. This can help visitors find the navigation again or Reread the ad (so beautiful to think about). As JavaScript has become more and more widely used in recent years, sliding effects are everywhere, so I followed suit and made the return to top function a sliding effect. Later, in order to better fit the physical characteristics, it was modified to have a decelerating sliding effect.

First let’s talk about the principle. We will get the distance from the scroll bar to the top of the page, and then move it up a certain distance; then get the distance from the scroll bar to the top of the page, and move it up a certain distance (smaller than the last time a little); and so on...
Let’s start with the code:

Copy the code The code is as follows:

document.documentElement.scrollTop, document.body.scrollTop, window.scrollY are actually the same, but they only work in some browsers. As for which one works in which browsers, you can debug it yourself.
How to use?

Copy code The code is as follows:

TOP