I've made a webpage. I want to implimenet the feature which scrolls the webpage to the location of href target of menu anchors. My code is as following
var myscroll = {}; myscroll.list = document.getElementsByClassName("navbar-right")[0].getElementsByTagName("li"); myscroll.bodypos = function getScrollY() { scrOfY = 0; if (typeof(window.pageYOffset) == 'number') { //Netscape compliant scrOfY = window.pageYOffset; } else if (document.body && (document.body.scrollLeft || document.body.scrollTop)) { //DOM compliant scrOfY = document.body.scrollTop; } else if (document.documentElement && (document.documentElement.scrollLeft || document.documentElement.scrollTop)) { //IE6 standards compliant mode scrOfY = document.documentElement.scrollTop; } return scrOfY; } function getScrollpos(idname) { return document.getElementById(idname).offsetTop; } myscroll.point = []; myscroll.point[0] = getScrollpos("home"); myscroll.point[1] = getScrollpos("artists"); myscroll.point[2] = getScrollpos("songs"); myscroll.point[3] = getScrollpos("beats"); myscroll.point[4] = getScrollpos("contact"); function removeclass() { for (var i = 0; i < 5; i++) { myscroll.list[i].className = ""; } } window.addEventListener('scroll', function(e) { if (myscroll.bodypos() >= myscroll.point[0]) { removeclass(); myscroll.list[0].className = "active"; } if (myscroll.bodypos() >= myscroll.point[1]) { removeclass(); myscroll.list[1].className = "active"; } if (myscroll.bodypos() >= myscroll.point[2]) { removeclass(); myscroll.list[2].className = "active"; } if (myscroll.bodypos() >= myscroll.point[3]) { removeclass(); myscroll.list[3].className = "active"; } if (myscroll.bodypos() >= myscroll.point[4]) { removeclass(); myscroll.list[4].className = "active"; } }); for (var j = 0; j < 5; j++) { (function(j) { myscroll.list[j].anchor = document.getElementsByClassName("navbar-right")[0].getElementsByTagName("li")[j].getElementsByTagName("a")[0]; myscroll.list[j].anchor.addEventListener("click", function() { if ((document.body.scrollTop != undefined) && (document.body.scrollTop < myscroll.point[j])) { var clr1 = setInterval(function() { if (document.body.scrollTop < myscroll.point[j] - 10) { document.body.scrollTop += 3; } else { document.body.scrollTop = myscroll.point[j]; clearInterval(clr1); } }, 1); } if ((document.documentElement.scrollTop != undefined) && (document.documentElement.scrollTop < myscroll.point[j])) { var clr2 = setInterval(function() { if (document.documentElement.scrollTop < myscroll.point[j] - 10) { document.documentElement.scrollTop += 3; } else { document.documentElement.scrollTop = myscroll.point[j]; clearInterval(clr2); } }, 1); } if ((document.body.scrollTop != undefined) && (document.body.scrollTop > myscroll.point[j])) { var clr3 = setInterval(function() { if (document.body.scrollTop >= myscroll.point[j] + 4) { document.body.scrollTop -= 3; } else { document.body.scrollTop = myscroll.point[j]; clearInterval(clr3); } }, 1); } if ((document.documentElement.scrollTop != undefined) && (document.documentElement.scrollTop > myscroll.point[j])) { var clr4 = setInterval(function() { if (document.documentElement.scrollTop >= myscroll.point[j] + 4) { document.documentElement.scrollTop -= 3; } else { document.documentElement.scrollTop = myscroll.point[j]; clearInterval(clr4); } }, 1); } alert(j); }, true); }(j)); }
#navbar, #navbar a:link, #navbar a:visited, #navbar a:hover { position: fixed; color: red !important; } #home { width: 500px; height: 500px; background-color: black; display: block; } #artists { width: 500px; height: 500px; background-color: gray; display: block; } #songs { width: 500px; height: 500px; background-color: yellow; display: block; } #beats { width: 500px; height: 500px; background-color: blue; display: block; } #contact { width: 500px; height: 500px; background-color: green; display: block; }
<div id="navbar" class="navbar-collapse collapse"> <ul class="nav navbar-nav navbar-right"> <li class="active"><a href="#">Home</a> </li> <li><a href="#artists">Artists</a> </li> <li><a href="#songs">Songs</a> </li> <li><a href="#beats">Beats</a> </li> <li><a href="#contact">Contact</a> </li> </ul> </div> <div id="home"></div> <div id="artists"></div> <div id="songs"></div> <div id="beats"></div> <div id="contact"></div>
As such the code doesn't do what it is supposed to. If we remove href
attributes of menu's anchor tags then the code works as expected but with one bug. The problem with the href
tags is that before the onclick
function could do anything the webpages scrolls quickly to the href target
. Other posts say returntning false with onclick would disable the href
target. The problem is that I am not using onclick
; I am using addEventListener("click")
. I tried returning both false
and true
but nothing worked. So,
false
stops href function of anchor elements? Now I know that preventDefault
will do what I want. But I want to know how to acheive the same by returning false. Now comes the bug. When I click on contact
link it scrolls down to the bottom of page and remains fixed there. If I scroll upwards then the page is automatically scrolled to bottom.
var myscroll = {}; myscroll.list = document.getElementsByClassName("navbar-right")[0].getElementsByTagName("li"); myscroll.bodypos = function getScrollY() { scrOfY = 0; if (typeof(window.pageYOffset) == 'number') { //Netscape compliant scrOfY = window.pageYOffset; } else if (document.body && (document.body.scrollLeft || document.body.scrollTop)) { //DOM compliant scrOfY = document.body.scrollTop; } else if (document.documentElement && (document.documentElement.scrollLeft || document.documentElement.scrollTop)) { //IE6 standards compliant mode scrOfY = document.documentElement.scrollTop; } return scrOfY; } function getScrollpos(idname) { return document.getElementById(idname).offsetTop; } myscroll.point = []; myscroll.point[0] = getScrollpos("home"); myscroll.point[1] = getScrollpos("artists"); myscroll.point[2] = getScrollpos("songs"); myscroll.point[3] = getScrollpos("beats"); myscroll.point[4] = getScrollpos("contact"); function removeclass() { for (var i = 0; i < 5; i++) { myscroll.list[i].className = ""; } } window.addEventListener('scroll', function(e) { if (myscroll.bodypos() >= myscroll.point[0]) { removeclass(); myscroll.list[0].className = "active"; } if (myscroll.bodypos() >= myscroll.point[1]) { removeclass(); myscroll.list[1].className = "active"; } if (myscroll.bodypos() >= myscroll.point[2]) { removeclass(); myscroll.list[2].className = "active"; } if (myscroll.bodypos() >= myscroll.point[3]) { removeclass(); myscroll.list[3].className = "active"; } if (myscroll.bodypos() >= myscroll.point[4]) { removeclass(); myscroll.list[4].className = "active"; } }); for (var j = 0; j < 5; j++) { (function(j) { myscroll.list[j].anchor = document.getElementsByClassName("navbar-right")[0].getElementsByTagName("li")[j].getElementsByTagName("a")[0]; myscroll.list[j].anchor.addEventListener("click", function(event) { event.preventDefault(); if ((document.body.scrollTop != undefined) && (document.body.scrollTop < myscroll.point[j])) { var clr1 = setInterval(function() { if (document.body.scrollTop < myscroll.point[j] - 10) { document.body.scrollTop += 3; } else { document.body.scrollTop = myscroll.point[j]; clearInterval(clr1); } }, 1); } if ((document.documentElement.scrollTop != undefined) && (document.documentElement.scrollTop < myscroll.point[j])) { var clr2 = setInterval(function() { if (document.documentElement.scrollTop < myscroll.point[j] - 10) { document.documentElement.scrollTop += 3; } else { document.documentElement.scrollTop = myscroll.point[j]; clearInterval(clr2); } }, 1); } if ((document.body.scrollTop != undefined) && (document.body.scrollTop > myscroll.point[j])) { var clr3 = setInterval(function() { if (document.body.scrollTop >= myscroll.point[j] + 4) { document.body.scrollTop -= 3; } else { document.body.scrollTop = myscroll.point[j]; clearInterval(clr3); } }, 1); } if ((document.documentElement.scrollTop != undefined) && (document.documentElement.scrollTop > myscroll.point[j])) { var clr4 = setInterval(function() { if (document.documentElement.scrollTop >= myscroll.point[j] + 4) { document.documentElement.scrollTop -= 3; } else { document.documentElement.scrollTop = myscroll.point[j]; clearInterval(clr4); } }, 1); } alert(j); }, true); }(j)); }
#navbar, #navbar a:link, #navbar a:visited, #navbar a:hover { position: fixed; color: red !important; } #home { width: 500px; height: 500px; background-color: black; display: block; } #artists { width: 500px; height: 500px; background-color: gray; display: block; } #songs { width: 500px; height: 500px; background-color: yellow; display: block; } #beats { width: 500px; height: 500px; background-color: blue; display: block; } #contact { width: 500px; height: 500px; background-color: green; display: block; }
<div id="navbar" class="navbar-collapse collapse"> <ul class="nav navbar-nav navbar-right"> <li class="active"><a href="#">Home</a> </li> <li><a href="#artists">Artists</a> </li> <li><a href="#songs">Songs</a> </li> <li><a href="#beats">Beats</a> </li> <li><a href="#contact">Contact</a> </li> </ul> </div> <div id="home"></div> <div id="artists"></div> <div id="songs"></div> <div id="beats"></div> <div id="contact"></div>
Use preventDefault()
on the event, to stop the default for the click
event to be executed.
window.addEventListener('scroll', function(e) {
e.preventDefault();
...
Then do your thing in your handler, and at the end, manually update the window.location
with the value of the event target's href
attribute.
EDIT
RE the comment: your event still bubbles, only the default action is prevented. To stop it from bubbling up, there is event.stopPropagation()
.
The default action for you event is simply to set the window.location
to the value of your event target's href
attribute
window.location = e.target.getAttribute('href');
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