Skip to content

Instantly share code, notes, and snippets.

@handleman
Forked from justinmc/anchor_smooth_scroll.js
Last active August 29, 2015 14:27
Show Gist options
  • Save handleman/e3d876e1e6e83a0583b9 to your computer and use it in GitHub Desktop.
Save handleman/e3d876e1e6e83a0583b9 to your computer and use it in GitHub Desktop.
Anchor Smooth Scroll - Angular Directive
/**~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Anchor Smooth Scroll - Smooth scroll to the given anchor on click
* adapted from this stackoverflow answer: http://stackoverflow.com/a/21918502/257494
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
angular.module('yourapp').directive('anchorSmoothScroll', function($location) {
'use strict';
return {
restrict: 'A',
replace: false,
scope: {
'anchorSmoothScroll': '@'
},
link: function($scope, $element, $attrs) {
initialize();
/* initialize -
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
function initialize() {
createEventListeners();
}
/* createEventListeners -
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
function createEventListeners() {
// listen for a click
$element.on('click', function() {
// set the hash like a normal anchor scroll
$location.hash($scope.anchorSmoothScroll);
// smooth scroll to the passed in element
scrollTo($scope.anchorSmoothScroll);
});
}
/* scrollTo -
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
function scrollTo(eID) {
// This scrolling function
// is from http://www.itnewb.com/tutorial/Creating-the-Smooth-Scroll-Effect-with-JavaScript
var i;
var startY = currentYPosition();
var stopY = elmYPosition(eID);
var distance = stopY > startY ? stopY - startY : startY - stopY;
if (distance < 100) {
scrollTo(0, stopY); return;
}
var speed = Math.round(distance / 100);
if (speed >= 20) speed = 20;
var step = Math.round(distance / 25);
var leapY = stopY > startY ? startY + step : startY - step;
var timer = 0;
if (stopY > startY) {
for (i = startY; i < stopY; i += step) {
setTimeout('window.scrollTo(0, '+leapY+')', timer * speed);
leapY += step; if (leapY > stopY) leapY = stopY; timer++;
} return;
}
for (i = startY; i > stopY; i -= step) {
setTimeout('window.scrollTo(0, '+leapY+')', timer * speed);
leapY -= step; if (leapY < stopY) leapY = stopY; timer++;
}
}
/* currentYPosition -
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
function currentYPosition() {
// Firefox, Chrome, Opera, Safari
if (window.pageYOffset) {
return window.pageYOffset;
}
// Internet Explorer 6 - standards mode
if (document.documentElement && document.documentElement.scrollTop) {
return document.documentElement.scrollTop;
}
// Internet Explorer 6, 7 and 8
if (document.body.scrollTop) {
return document.body.scrollTop;
}
return 0;
}
/* scrollTo -
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
function elmYPosition(eID) {
var elm = document.getElementById(eID);
var y = elm.offsetTop;
var node = elm;
while (node.offsetParent && node.offsetParent != document.body) {
node = node.offsetParent;
y += node.offsetTop;
} return y;
}
}
};
});
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment