Javascript to determine beginning scroll position on page? - javascript

I have a site that features a "fixed" header, the problem is that it really messes up links that link further down the page a la "http://mysite.com/#lower_div_on_the_page"
Is it even possible to use javascript to do something like
if (URL has #hashtag) {starting scroll position = normal position + (my_header_height)}
Is this even possible?
EDIT:
Thanks for all the replies... really appreciated. For reference, I am DEFINITELY using jQuery... how would I do this with jQuery?

Yes, it's possible.
Here are the steps you need to take:
Set up a DOM Loaded event handler. There's more than one way to do this and here's a link to a web page that explains how to do this. Also if you're using a javascript framework such as jQuery (see .ready()) or Prototype.js (see observe extension) it would be a lot easier.
In the DOM loaded event handler function parse the URL (window.location) for the hashtag.
var hashTag = window.location.href;
hashTag = hashTag.substr(hashTag.indexOf('#') + 1);
// now hashTag contains the portion of the URL after the hash sign
Then if you recognize the anchor tag compute the desired scroll location based on that element's location in the DOM tree or whatever logic you would like to use. Again, jQuery (see .offset()) or Prototype.js (see cumulativeScrollOffset) should be able to help with determining the correct offset to scroll to.
Set the scroll of the page. Again jQuery (see .scrollTop()) or Prototype.js (see scrollTo) both have extensions to help with this.
Here's a jQuery example:
$(document).ready(function() {
var hashTag = window.location.href;
if(hashTag.indexOf('#') > 0)
{
hashTag = hashTag.substr(hashTag.indexOf('#'));
// now get the element's offset relative to the document
var offsetTop = $(hashTag).offset().top;
// and finally, scroll the document to that offset
$(document).scrollTop(offsetTop);
}
});

Sure is, you could do something as simple as:
if(window.location.hash != ''){
elementOffset = document.getElementById(window.location.hash.substr(1)).offsetTop;
window.scrollTo(0,elementOffset + my_header_height);
}
Using jQuery it'd obviously be simpler, and you would need to get extra offset depending on containing elements and such, but that should get you started.

Related

Chrome ignoring hashes in URL

I've spent quite a while trying to find answers for this issue, but haven't had any success. Basically I need to scroll the user to the contact portion of the website when they go to healthdollars.com/#contact. This works just fine in Safari, but in Chrome I haven't had any luck. I've tried using jQuery/Javascript to force the browser to scroll down, but I haven't been able to.
Does anyone have any ideas? It's driving me crazy - especially since it's such a simple thing to do.
Not a full answer but in Chrome if you disable Javascript I believe you get the desired behavior. This makes me believe that something in your JavaScript is preventing default browser behavior.
It looks to me like the target element doesn't exist when when page first loads. I don't have any problem if I navigate to the page and then add the hash.
if (window.location.hash.length && $(location.hash)) {
window.scrollTo(0, $(location.hash).offset().top)
}
check for a hash, find the element's page offset, and scroll there (x, y).
edit: I noticed that, in fact, the page starts at #contact, then scrolls back to the top. I agree with the other answerer that there's something on your page that's scrolling you to the top. I'd search for that before adding a hack.
You can do this with JS, for example` if you have JQuery.
$(function(){
// get the selector to scroll (#contact)
var $to = $(window.location.hash);
// jquery animate
$('html'/* or body */).animate({ scrollTop: $to.offset().top });
});
The name attribute doesn't exists in HTML 5 so chrome looks to have made the name attribute obsolete when you use the DOCTYPE html.
The other browsers have yet to catch up.
Change
<a name="contact"></a>
to
<a id="contact"></a>
Maybe this workaround with vanilla javascript can be useful:
// Get the HTMLElement that you want to scroll to.
var element = document.querySelector('#contact');
// Stories the height of element in the page.
var elementHeight = element.scrollHeight;
// Get the HTMLElement that will fire the scroll on{event}.
var trigger = document.querySelector('[href="#contact"]');
trigger.addEventListener('click', function (event) {
// Hide the hash from URL.
event.preventDefault();
// Call the scrollTo(width, height) method of window, for example.
window.scrollTo(0, elementHeight);
})

URL hash based slider

JS Fiddle
Original Idea / Another version of this question
Attention!
The other version of this idea/the original idea has been answered so if the other version works for you, your welcome :)
This question is still open
So here is my new idea that I am having trouble with. I want to make an image slider. The slider has all the images inside of it and when the page turns to a hash like #home I want the slider to update to a new image. The slider is floating. The other thing is I don't want it to scroll passed other images. I just want it to scroll directly to that image. I also needs to scroll vertically since the images are different widths. I feel bad that I am basically making a job request so this is what I think is right. I can write the code if someone tells me what I need to do.
Here is the code on JS Fiddle. I just have the link so it can be worked on:
//This also need to execute when the hash is updated/an anchor link is clicked
window.onLoad = function hashLogo() {
var hash = window.location.hash;
//Image 1 Hashes
var image1 = [
'#image1',
'#home'
];
//Image 2 Hashes
var image2 = [
'#image2',
'#about'
];
if (image1.indexOf(hash) > -1) {
//Do jQuery Sliding
}
if (image2.indexOf(hash) > -1) {
//Do jQuery Sliding
}
};
What I think you need is an event interception on the hashchange event:
$(window).hashchange( function(){
// Do something when the hash changes
// alert( location.hash );
});
If you also use Ben Alman's fabulous hashchange plugin (0.8kb), it will also ensure the event is polyfilled into browsers that don't support it.

Javascript substring method assistance

So long story short im working on a web app and using AJAX within it.
I'm trying to disable the default actions of links when clicked, attach a hash value to the link and then remove the "#" from the url.
the problem im having is that, although the hash values are being attached accordingly, the substring method isnt extracting the "#", it extracts the letter after it.....
here is my code. PS, i left my comments inthere so you get where im trying to go with this
so i dont know....my logic or setup may be wrong....
$(document).ready(function(){
//app vars
var mainHash = "index";
var menuBtn = $('.leftButton');
//~~~~~~load the index page at first go.
loadPage();
//~~~~~~~~~~~~~~~~~~~~~~~~~~~menu show/hide
menuBtn.click( function(){
$('#menu').toggleClass();
});
//Menu items on click , disable link default actions.
$('#menu a').click( hijackLinks );
//~~~~~~~~~~~~~~~~~~~~~~~~~~~functions for mobile index load AND hijacking app links to AJAX links.
function loadPage(url){
if( url == undefined){
$('#contentHere').load('index.html #content', hijackLinks);
window.location.hash = mainHash;
} else {
$('#contentHere').load(url + '#content', hijackLinks );
}
}
function hijackLinks(e){
var url = e.target.href;
e.preventDefault();
loadPage(e.target.href);
window.location.hash = $(this).attr("href").substring(1);
}
});
what im wanting is to remove the "#" from the url. What am i doing wrong, what am i not seeing/understanding?
ive tried substring/substr etc and both do the same thing in that no matter what numbers i choose to insert into the substrings params, they remove EVERYTHING BUT the "#" lol....
Thanks in advanced.
Well, you don't really change the link itself, you only change the window.location.hash, and the hash always has a "#" at the beginning.
What you need to do in order to change the entire url (and remove the '#') is to manipulate the browser history.
Although you should know it works only in newer browsers (the exact browser versions are in the link), so if you target your website to older too browsers you might need to think about having a fallback using the hash. If you decide to have such a fallback, I suggest searching for a plugin which does it instead of making it all yourself.

Google related bar - how to keep from showing up on my website

A new "google related" bar shows up at the bottom of my website. It displays links to my competitors and other things like maps, etc. It is tied in with users using the google toolbar. If anyone has any ideas on how I can disable from displaying on my web side I would sure appreciate it.
Taken from http://harrybailey.com/2011/08/hide-google-related-bar-on-your-website-with-css/
Google inserts an iframe into your html with the class .grelated-iframe
So hiding it is as simple as including the following css:
iframe.grelated-iframe {
display: none;
}
Google removed div and frame names and put everything to important so original answer no longer works on my site. We need to wait for the iframe to be created and then hide it by classname. Couldn't get .delay to work, but this does...today anyway.
$(document).ready(function() {
setTimeout(function(){
$(‘.notranslate’).hide();},1000);
});
Following javascript code tries to find the google related iframe as soon as the window finishes loading. If found, it is made hidden, else an interval of one second is initialized, which checks for the specified iframe and makes it hidden as soon as it is found on page.
$(window).load(function (){
var giframe = null;
var giframecnt = 0;
var giframetmr = -1;
giframe = $("body > iframe.notranslate")[0];
if(giframe != null)
$(giframe).css("display", "none");
else
giframetmr = setInterval(function(){
giframe = $("body > iframe.notranslate")[0];
if(giframe != null) {
clearInterval(giframetmr);
$(giframe).css("display", "none");
} else if(giframecnt >= 20)
clearInterval(giframetmr);
else
giframecnt++;
}, 1000);});
Find the parent DIV element that contains the stuff in the bar. If it has an id or name attribute, and you can control the page CSS then simply add a rule for the element, i.e. if you see something like
<div id="footer-bar-div".....
then add a CSS rule
#footer-bar-div {display:none ! important}
This will not work if the bar is inside an iframe element, but even in that case you should be able to hide it using javascript, but you will need to find the name/id of the frame, i.e.:
var badFrame = document.getElementById('badFrameId').contentWindow;
badFrame.getElementById('footer-bar-div').style.display='none';
if the frame has a name, then instead you should access it with:
var badFrame = window.frames['badFrameName']
There is also a chance that the bar is generated on-the-fly using javascript. If it is added to the end of the page you can simply add a <noscript> tag at the end of your content - this will prevent the javascript from executing. This is an old trick so it might not always work.

goto HTML document location dynamically

My page adds # to the html programatically and have this in the tag
function InsertTag(){
//Add <a name="spot"></a> to the middle of this document
}
window.addEventListener('load', InsertTag, false);
my question is how can I make the document then jump to #spot?
Here's a suggestion: use id's instead. If you have:
<div id="something">
Then page.html#something will take you straight to that div. It doesn't have to be a div, it can be used on any element. If you can manipulate the DOM to add that anchor, I am pretty sure you'll be able to do this.
Now... To get there, you can use:
// this approach should work with anchors too
window.location.hash = 'something';
// or scroll silently to position
var node = document.getElementById('something');
window.scroll(0, node.offsetTop);
See it in action here: http://ablazex.com/demos/jump.html
There are subtle differences between the methods. Eg: The first one will cause the location on the address bar to be updated, the second one won't.
If you want it to look nicer you can use a jQuery plugin, like ScrollTo.
Try
window.location = currentUrl+'#spot';
where currentUrl is a variable having the address of the current url
You can try this.
var el = document.getElementById('spot');
var eloffsetTop = el.offsetTop;
window.scroll(0,eloffsetTop);

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