HTML DOM scrollTop Property
Example
Get the number of pixels the content of a <div> element is scrolled horizontally and vertically:
var elmnt = document.getElementById("myDIV");
var x = elmnt.scrollLeft;
var y = elmnt.scrollTop;
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More "Try it Yourself" examples below.
Definition and Usage
The scrollTop property sets or returns the number of pixels an element's content is scrolled vertically.
Tip: Use the scrollLeft property to set or return the number of pixels an element's content is scrolled horizontally.
Tip: To add scrollbars to an element, use the CSS overflow property.
Tip: The onscroll event occurs when an element's scrollbar is being scrolled.
Browser Support
| Property | |||||
|---|---|---|---|---|---|
| scrollTop | Yes | Yes | Yes | Yes | Yes |
Syntax
Return the scrollTop property:
element.scrollTop
Set the scrollTop property:
element.scrollTop = pixels
Property Values
| Value | Description |
|---|---|
| pixels |
Specifies the number of pixels the element's content is scrolled vertically. Special notes:
|
Technical Details
| Return Value: | A Number, representing the number of pixels that the element's content has been scrolled vertically |
|---|
More Examples
Example
Scroll the contents of a <div> element TO 50 pixels horizontally and 10 pixels vertically:
var elmnt = document.getElementById("myDIV");
elmnt.scrollLeft = 50;
elmnt.scrollTop = 10;
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Example
Scroll the contents of a <div> element BY 50 pixels horizontally and 10 pixels vertically:
var elmnt = document.getElementById("myDIV");
elmnt.scrollLeft += 50;
elmnt.scrollTop += 10;
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Example
Scroll the contents of <body> by 30 pixels horizontally and 10 pixels vertically:
var body = document.body; // Safari
var html = document.documentElement; //
Chrome, Firefox, IE and Opera places the overflow at the <html> level, unless else is specified. Therefore, we use the
documentElement property for these browsers
body.scrollLeft += 30;
body.scrollTop += 10;
html.scrollLeft += 30;
html.scrollTop += 10;
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Example
Toggle between class names on different scroll positions - When the user scrolls down 50 pixels from the top of the page, the class name "test" will be added to an element (and removed when scrolled up again).
window.onscroll = function() {myFunction()};
function myFunction() {
if (document.body.scrollTop > 50 || document.documentElement.scrollTop > 50) {
document.getElementById("myP").className = "test";
} else {
document.getElementById("myP").className = "";
}
}
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Example
Slide in an element when the user has scrolled down 350 pixels from the top of the page (add the slideUp class):
window.onscroll = function() {myFunction()};
function myFunction() {
if (document.body.scrollTop > 350 || document.documentElement.scrollTop > 350) {
document.getElementById("myImg").className = "slideUp";
}
}
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Example
Draw a triangle on scroll:
<!-- Use SVG to draw the triangle (has to be <path>) -->
<svg id="mySVG">
<path fill="none" stroke="red" stroke-width="3" id="triangle" d="M150 0 L75 200 L225 200 Z">
</svg>
<script>
// Get the id of the <path> element and the length of <path>
var triangle = document.getElementById("triangle");
var length = triangle.getTotalLength();
// The start position of the drawing
triangle.style.strokeDasharray = length;
// Hide the triangle by offsetting dash. Remove this line to show the triangle before scroll draw
triangle.style.strokeDashoffset = length;
// Find scroll percentage on scroll (using cross-browser properties), and offset dash same amount as percentage scrolled
window.addEventListener("scroll", myFunction);
function myFunction() {
var scrollpercent = (document.body.scrollTop + document.documentElement.scrollTop) / (document.documentElement.scrollHeight - document.documentElement.clientHeight);
var draw = length * scrollpercent;
// Reverse the drawing (when scrolling upwards)
triangle.style.strokeDashoffset = length - draw;
}
</script>
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