I am looking to calculate the distance between an element and the top of the document window. On scroll I am able to get the initial value but it does not change. How can I find this value and what the number has changed to on scroll?
JS:
$(function() {
$(window).scroll(function() {
var h1 = $("h1");
console.log(h1.offset().top)
});
});
HTML:
<div id="cover">
<h1>hello sir</h1>
</div>
getElementById('box'). offsetHeight; var clientHeight = document. getElementById('box'). clientHeight; if (offsetHeight <= scrollTop + clientHeight) { // This is called before scroll end! } }, false );
forward, then scroll offset is the amount the top of the sliver has been scrolled past the top of the viewport. This value is typically used to compute whether this sliver should still protrude into the viewport via SliverGeometry.
The offset() method set or returns the offset coordinates for the selected elements, relative to the document. When used to return the offset: This method returns the offset coordinates of the FIRST matched element. It returns an object with 2 properties; the top and left positions in pixels.
The jQuery offset() function is a built-in function in jQuery, by which we can return the offset of the bottom coordinate. The jQuery offset() function only specifies the top and left properties position, but with the help of top property and outerHeight() function, we can get the bottom position for elements.
Compare the offset of the <h1>
element to how far down the page the user has scrolled. The $(window).scrollTop()
function will get you the amount the user has scrolled down so:
$(window).scroll(function() {
var $h1 = $("h1");
var window_offset = $h1.offset().top - $(window).scrollTop();
});
If you hate arithmetic (and extra function calls), this should do the trick:
$(function() {
var h1 = document.getElementsByTagName("h1")[0];
$(window).scroll(function() {
console.log(h1.getBoundingClientRect().top);
});
});
This is exactly what getBoundingClientRect() was made for.
You can use this function to get the scroll offset of the window:
function getScrollXY() {
var scrOfX = 0, scrOfY = 0;
if( typeof( window.pageYOffset ) == 'number' ) {
//Netscape compliant
scrOfY = window.pageYOffset;
scrOfX = window.pageXOffset;
} else if( document.body && ( document.body.scrollLeft || document.body.scrollTop ) ) {
//DOM compliant
scrOfY = document.body.scrollTop;
scrOfX = document.body.scrollLeft;
} else if( document.documentElement && ( document.documentElement.scrollLeft || document.documentElement.scrollTop ) ) {
//IE6 standards compliant mode
scrOfY = document.documentElement.scrollTop;
scrOfX = document.documentElement.scrollLeft;
}
return [ scrOfX, scrOfY ];
}
Then you can use the offsets in your function to determine the real position of your element:
$(function() {
$(window).scroll(function() {
var h1 = $("h1");
var offs = getScrollXY();
console.log(h1.offset().top - offs[1]);
});
});
Theoretically, this should work in all browsers, but, frankly, I didn't do too much testing.
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