Use jQuery to detect web scrolling percentage

The following jQuery code snippet demonstrates how to trigger an event action when a user scrolls to a specific percentage of the webpage. Tests show that when capturing mouse scroll events, it is best to use values ??between 55% and 100%.

$(document).ready(function(){

// 例子：滾動到網(wǎng)頁75%時顯示一個div
var webpage = $("body");
var webpage_height = webpage.height();
var trigger_height = webpage_height * 0.75;


if ($(window).scrollTop() > (webpage_height-trigger_height)) {
    $("#divtoshow").show();
}

});

jQuery scroll event FAQs (FAQs)

How to detect scrolling events in jQuery?

Detecting scrolling events in jQuery is very simple. The built-in .scroll() method can be used. This method triggers a scroll event, or attaches a function that runs when the scroll event occurs. Here is a simple example:

$(window).scroll(function(){
  console.log("檢測到滾動事件！");
});

In this code, whenever a scroll event occurs in the window, the message "Scroll event detected!" will be recorded to the console.

How to determine the direction of jQuery scroll event?

Determining the direction of the jQuery scroll event requires more operations. The current scroll position needs to be compared with the previous scroll position. Here is a basic example:

var lastScrollTop = 0;
$(window).scroll(function(){
  var currentScrollTop = $(this).scrollTop();
  if (currentScrollTop > lastScrollTop){
    console.log("向下滾動");
  } else if (currentScrollTop < lastScrollTop) {
    console.log("向上滾動");
  }
  lastScrollTop = currentScrollTop;
});

In this code, we store the last scroll position in a variable. Then, in each scroll event, we compare the current scroll position with the last scroll position to determine the direction of the scroll.

What is the function of the

method in jQuery? .scrollTop()

The

method in jQuery gets or sets the current vertical position of the scroll bar that matches the first element in the element set. When called without parameters, it returns to the scroll position; when called with parameters, it sets the scroll position. .scrollTop()

How to trigger a function when the page scrolls to a specific position?

Yes, you can trigger the function when the page scrolls to a specific position. You can do this by checking the current scroll position in the scroll event handler. Here is an example:

$(window).scroll(function(){
  if ($(this).scrollTop() > 200){
    console.log("滾動超過200像素");
  }
});

In this code, whenever the scroll position exceeds 200 pixels, the message "Scroll exceeds 200 pixels" will be recorded to the console.

How to animate scrolling events in jQuery?

You can use the

method to animation scrolling events in jQuery. This method allows you to create custom animation effects on numbers. Here is an example: .animate()

$('html, body').animate({
  scrollTop: $("#myDiv").offset().top
}, 2000);

In this code, the page will scroll smoothly to the top position of the element with ID "myDiv" in 2 seconds.

Can I stop or block scrolling events in jQuery?

No, you cannot stop or block scrolling events in jQuery. The scrolling event is a native browser event and cannot be cancelled. However, you can block default actions for certain events that may cause scrolling, such as mouse wheel events.

How to detect scrolling events on specific elements in jQuery?

Scrolling events on specific elements in jQuery can be detected by attaching the

method to this element. Here is an example: .scroll()

$("#myDiv").scroll(function(){
  console.log("在#myDiv上檢測到滾動事件！");
});

In this code, the scroll event on the element ID "myDiv" records the message "Scroll event was detected on #myDiv!" to the console.

Can I detect horizontal scrolling events in jQuery?

Yes, you can use the .scrollLeft() method to detect horizontal scrolling events in jQuery. This method is similar to the .scrollTop() method, but is used for horizontal scrolling.

How to detect the end of a scroll event in jQuery?

The end of a scroll event in jQuery can be detected by comparing the current scroll position with the total scrollable height. Here is an example:

$(document).ready(function(){

// 例子：滾動到網(wǎng)頁75%時顯示一個div
var webpage = $("body");
var webpage_height = webpage.height();
var trigger_height = webpage_height * 0.75;


if ($(window).scrollTop() > (webpage_height-trigger_height)) {
    $("#divtoshow").show();
}

});

In this code, when the scroll end is reached, the message "Scroll end detected!" will be recorded to the console.

Can I detect scrolling events on mobile devices in jQuery?

Yes, you can detect scrolling events on mobile devices in jQuery. .scroll() Method works the same way on mobile devices as it works on desktop browsers. However, remember that mobile browsers may handle scrolling events differently than desktop browsers, so it is always recommended to test your code on multiple devices.

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