getElementsByClassName doesn't work properly at Element nodes [duplicate] - javascript

(I ask my question again after the first one was terribly formulated)
I face the following problem:
<div class="testA" id="test1"></div>
The above written element is predefined. I now load a xml tree via XMLHttpRequest & Co. delivering the following response:
<response>
<div class="colorSelector" id="0-0">
<div class="gbSelector" id="1-0">
<table style="none" id="2-0"></table>
</div>
</div>
</response>
I now append the first div using
request.responseXML.getElementsByTagName("response")[0]
.getElementsByTagName("div")[0]
into the predefined div
<div class="testA" id="test1">
The final document looks like this (checked using development tools):
<div class="testA" id="test1">
<div class="colorSelector" id="0-0">
<div class="gbSelector" id="1-0">
<table style="none" id="2-0"></table>
</div>
</div>
</div>
When I now try to get the element <div class="colorSelector" id="0-0"> using getElementById("0-0") I get the expected result.
But using getElementsByClassName("colorSelector") returns [].
Did I miss something? Is it probably a leftover of the fact the nodes were of type Element and not HTMLElement?

colorSelector is commented out. JavaScript only works within the DOM, and commented out portions aren't in the DOM.

Since you said that your getElementById("0-0") is successful, then clearly you don't actually have the nodes commented out.
I'm guessing you're doing:
document.getElementById("0-0").getElementsByClassName('colorSelector');
...which will not work because the element selected by ID does not have any descendants with that class.
Since you show HTML comments in the markup, I'd also wonder if you have some different element on the page with the ID "0-0". Take a look for that.
If your nodes are actually commented out, you'll need to first select the comment, and replace it with the markup contained inside:
var container = document.getElementById('test1'),
comment = container.firstChild;
while( comment && comment.nodeType !== 8 ) {
comment = comment.nextSibling;
}
if( comment ) {
container.innerHTML = comment.nodeValue;
}
...resulting in:
<div class="testA" id="test1">
<div class="colorSelector" id="0-0">
<div class="gbSelector" id="1-0">
<table style="none" id="2-0"></table>
</div>
</div>
</div>
...but there again, this doesn't seem likely since your getElementsById does work.

Here's a way to do it for Firefox, Opera, Chrome and Safari. Basically, you just do div.innerHTML = div.innerHTML to reinterpret its content as HTML, which will make that class attribute from the XML file be treated as an HTML class name.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title></title>
<script>
window.addEventListener("DOMContentLoaded", function() {
var div = document.getElementsByTagName("div")[0];
var req = new XMLHttpRequest();
req.onreadystatechange = function() {
if (this.readyState === 4 && this.status === 200) {
var doc = this.responseXML;
div.appendChild(document.importNode(doc.getElementsByTagName("response")[0].getElementsByTagName("div")[0], true));
div.innerHTML = div.innerHTML;
alert(document.getElementsByClassName("colorSelector").length);
}
};
req.open("GET", "div.xml");
req.send();
}, false);
</script>
</head>
<body>
<div class="testA"></div>
</body>
</html>
Remove the this.status === 200 if you're testing locally in browsers that support xhr locally.
The importNode() function doesn't seem to work in IE (9 for example). I get a vague "interface not supported" error.
You could also do it this way:
var doc = this.responseXML;
var markup = (new XMLSerializer()).serializeToString(doc.getElementsByTagName("response")[0].getElementsByTagName("div")[0]);
div.innerHTML = markup;
as long as the markup is HTML-friendly as far as end tags for empty elements are concerned.

<!--<div class="colorSelector" id="0-0">
<div class="gbSelector" id="1-0">
<table style="none" id="2-0"></table>
</div>
</div>-->
The above code is gray for a reason: it's a comment. Comments aren't parsed by the browser at all and have no influence on the page whatsoever.
You'll have to parse the HTML, read the comments, and make a new DOM object with the contents of the comment.

Please describe what you are doing with the returned results. There is a significant difference between a nodeList and a node, nodeLists are LIVE.
So if you assign a nodeList returned by getElementsByClassName() (or similar) to a variable, this variable will change when you remove the nodes inside the nodeList from the DOM.

I now append the first div
How do you do that? What you have in the responseXML are XML elements, and not HTML elements.
You shouldn't be able to appendChild them into a non-XHTML HTML document;
actually you shouldn't be able to appendChild them into another document at all, you're supposed to use importNode to get elements from one document to another, otherwise you should get WRONG_DOCUMENT_ERR;
even if you managed to insert them into an HTML due to browser laxness, they're still XML elements and are not semantically HTML elements. Consequently there is nothing special about the class attributes; just having that name doesn't make the attribute actually represent a class. getElementsByClassName won't return elements just because they have attributes with the name class; they have to be elements whose language definition associates the attributes with the concept of classness (which in general means HTML, XHTML or SVG).
(The same should be true of the id attributes; just having an attribute called id doesn't make it conceptually an ID. So getElementById shouldn't be working. There is a way to associate arbitrary XML attributes with ID-ness, which you don't get with class-ness, by using an <!ATTLIST declaration in the doctype. Not usually worth bothering with though. Also xml:id is a special case, in implementations that support XML ID.)
You could potentially make it work if you were using a native-XHTML page by putting suitable xmlns attributes on the content to make it actual-XHTML and not just arbitrary-XML, and then using importNode. But in general this isn't worth it; it tends to be simpler to return HTML markup strings (typically in JSON), or raw XML data from which the client-side script can construct the HTML elements itself.

Related

json & JavaScript replacing html h1 heading?

When I reload my browser to show some json data the JavaScript code keeps replacing my HTML code? How can I correct the problem?
JavaScript code:
$.getJSON('https://jsonplaceholder.typicode.com/posts/1', function, data) {
document.write(data.title);
};
HTML Code:
<div class="container">
<div id="json_example">
<h1>json Example</h1>
</div>
</div>
Don't use document.write() as it replaces fully built HTML documents with the new content. document.write() should only ever be used to construct dynamic pages while the page is being built.
Instead, just populate some pre-existing element with data.title,
As in:
$.getJSON('https://jsonplaceholder.typicode.com/posts/1', function, data) {
$("#output").text(data.title);
};
<div class="container">
<div id="json_example">
<h1>json Example</h1>
<span id="output"></span>
</div>
</div>
You are using document.write() which takes your document, and replaces it's content with the content you supply to the function. If you want to replace just the content of the <div id="json_example"></div> element, then you can use the following snippet in place of the document.write():
$("#json_example").text(data.title);
For non jQuery-version:
document.querySelector("#json_example").innerText = data.title;
If you want to replace the content of the <h1> the correct selector would be #json_example h1 instead.
In all the snippets what you do is find the element you want to change the content of using a CSS-selector. Both jQuery and pure Javascript supports this since IE8.
After finding the correct element, you set the elements content text to the content you want.
NOTE! Do NOT use innerHtml or .html() to set the content, as that opens you to script injections. Only use those methods when you generate the HTML yourself on the fly, in the browser. Even your database needs to be considered dirty.
try this
$.getJSON('https://jsonplaceholder.typicode.com/posts/1', function, data) {
document.getElementById("json_example").textContent = data.title;
};
Since you're already using jQuery here's a possible solution which uses it.
$.getJSON('https://jsonplaceholder.typicode.com/posts/1', function, data) {
$("#json_example").html("<h1>" + data.title + "</h1>");
};
This replaces your div html with your content.

Access view-source instead of prepared DOM

Hopefully I can explain my question correctly, so sorry in advance for any wrong use of jargon or other:
Is it possible to access with javascript the original markup as viewed in the source code rather then the code from the DOM after it has been 'modified'
Let's say an element #div1 has the actual text that will be used in another element with id #div2, in the source code the text will be visible in #div1 but in the DOM while inspecting #div1 will be empty and #div2 will have that text,
I know it would be a matter of the order of loading the scripts, but I was hoping there could be another way.
Hopefully this makes some sense.
Yep, the simpliest way to access original html is to place your js code before any other scripts (or place only libs like jquery before).
The second opportunity is to load document again with ajax, parse and get what you want. Here is code example:
<div id="div1">
Hello
</div>
<div id="div2">
</div>
<script type="text/javascript" src="https://code.jquery.com/jquery-1.12.4.min.js"></script>
<script>
$('#div2').html($('#div1').html())
$('#div1').html('')
</script>
<script>
alert($('#div1').html())
// ajax get
// empty string in get request means current location
$.get("", function (html) {
var el = $(html).filter('#div1');
alert(el.html())
});
</script>

Any way to get nearby html nodes different from current node's tag name in NodeJS?

Let's say I have the following html code..
<html>
<head></head>
<body>
<div>
<input type ="text">
<img src = "pic.jpg">
Home
</div>
</body>
</html>
And I want to look at the nodes around an element that's on the same level. For example, from the above html code, is it possible to do something like...
$("input").returnNodesOnSameLevel()
and it can return a list of nodes which here would contain [< input...>, < a...> ] ?
I'm using NodeJS's request module to grab the page source and then using Cheerio to do my parsing. The sibling() only returns nodes of the same tag name which makes sense. If there's a better module or another way to do this, please let me know.
Thank you.
If $("input").siblings() doesn't work, you could try: $("input").parent().children()

Insert just opening HTML tags after an element?

I would like to insert a couple of opening DIV tags after the H1 element on a page, without inserting the corresponding closing tags (since the closing tags are contained in an included footer file which I don't have access to).
i.e.
Existing code:
<body>
<h1>Heading One</h1>
... page content...
</div>
</div>
</body>
New code:
<body>
<h1>Heading One</h1>
<div id="foo">
<div id="baa">
... page content...
</div>
</div>
</body>
DOM methods insert the div as a complete (closed) element, 'createTextNode' inserts escaped characters and 'innerHTML' needs an element to insert into. Have even tried to insert a script element with document.write without any luck.
Any ideas (jQuery would be fine)?
Update
The following worked:
document.body.innerHTML = document.body.innerHTML.replace('</h1>','</h1><div id="foo"><div id="baa">')
As pointed out by Asad the solution (which now seems obvious of course) is to use string methods on the HTML rather than DOM methods.
If you're dealing with DOM manipulation, use DOM manipulation methods. If you're dealing with HTML manipulation, use string manipulation methods.
h1.parentElement.innerHTML = h1.parentElement.innerHTML.replace("<h1>Heading One</h1>","<h1>Heading One</h1><div><div>");
i think this will answer your question, it is all about valid XML formation.
http://www.w3schools.com/xml/xml_syntax.asp
Forget DOM methods, insert it as a string using .replace().
Your approach is fundamentally wrong. The browser parses the DOM as it sees it, and automatically closes any tags that ought to be closed. It's impossible to use JavaScript to insert only the opening tag.
You say "the closing tags are contained in an included footer file which I don't have access to." Closed tags that haven't been opened are ignored, so as far as the DOM parser is concerned, those closing tags don't exist.
Your solution is either:
Put the opening tags in a header, or somewhere else on the server-side, or
Use JavaScript to grab ALL the following DOM elements, including the footer, and .wrap() them all in the desired divs.
This kind of practice seems a bit unorthodox, but perhaps something like this would help.
Existing HTML
<h1 id="testH1">Test H1</h1>
<div id="existingDiv">
<div id="existingDivContent">Existing Div Content</div>
</div>
New HTML
<h1 id="testH1">Test H1</h1>
<div id="newDiv">
<div id="existingDiv">
<div id="existingDivContent">Existing Div Content</div>
</div>
</div>
JS
The javascript is fairly rudimentary, but I think the concept can be applied to safely and properly achieve your goal.
$(document).ready(function() {
//-- parent node you wish to copy
var existingDiv = $('#existingDiv');
//-- new parent div node
var newDiv = $('<div id="newDiv">');
//-- where we want to insert the new parent node
var testH1 = $('#testH1');
//-- stuff our previous parent node into our new parent node
newDiv.html(existingDiv);
//-- insert into the DOM
testH1.after(newDiv);
});
http://jsfiddle.net/8qzvN/

best way to inject html using javascript

I'm hoping that this isn't too subjective. I feel there is a definitive answer so here goes.
I want to create this html on the fly using JS (no libraries):
Play
Mute
<div id="progressBarOuter">
<div id="bytesLoaded"></div>
<div id="progressBar"></div>
</div>
<div id="currentTime">0:00</div>
<div id="totalTime">0:00</div>
using javascript. I know I can do this using createElement etc but it seems extremely long winded to do this for each element. Can anyone suggest a way to do this with more brevity.
I do not have access to a library in this project....so no jquery etc.
Keep your markup separate from your code:
You can embed the HTML snippets that you'll be using as hidden templates inside your HTML page and clone them on demand:
<style type="text/css">
#templates { display: none }
</style>
...
<script type="text/javascript">
var node = document.getElementById("tmp_audio").cloneNode(true);
node.id = ""; // Don't forget :)
// modify node contents with DOM manipulation
container.appendChild(node);
</script>
...
<div id="templates">
<div id="tmp_audio">
Play
Mute
<div class="progressBarOuter">
<div class="bytesLoaded"></div>
<div class="progressBar"></div>
</div>
<div class="currentTime">0:00</div>
<div class="totalTime">0:00</div>
</div>
</div>
Update: Note that I've converted the id attributes in the template to class attributes. This is to avoid having multiple elements on your page with the same ids. You probably don't even need the classes. You can access elements with:
node.getElementsByTagName("div")[4].innerHTML =
format(data.currentTime);
Alternatively, you can act on the HTML of the template:
<script type="text/javascript">
var tmp = document.getElementById("tmp_audio").innerHTML;
// modify template HTML with token replacement
container.innerHTML += tmp;
</script>
Shove the entire thing into a JS variable:
var html = 'Play';
html += 'Mute';
html += '<div id="progressBarOuter"><div id="bytesLoaded"></div><div id="progressBar"></div></div>';
html += '<div id="currentTime">0:00</div>';
html += '<div id="totalTime">0:00</div>';
Then:
document.getElementById("parentElement").innerHTML = html;
if you want theN:
document.getElementById("totalTime").innerHTML = "5:00";
You can use
<script type="text/javascript">
function appendHTML() {
var wrapper = document.createElement("div");
wrapper.innerHTML = '\
Play\
Mute\
<div id="progressBarOuter"> \
<div id="bytesLoaded"></div>\
<div id="progressBar"></div>\
</div>\
<div id="currentTime">0:00</div>\
<div id="totalTime">0:00</div>\
';
document.body.appendChild(wrapper);
}
</script>
If you live in 2019 and beyond read here.
With JavaScript es6 you can use string literals to create templates.
create a function that returns a string/template literal
function videoPlayerTemplate(data) {
return `
<h1>${data.header}</h1>
<p>${data.subheader}</p>
Play
Mute
<div id="progressBarOuter">
<div id="bytesLoaded"></div>
<div id="progressBar"></div>
</div>
<time id="currentTime">0:00</time>
<time id="totalTime">0:00</time>
`
}
Create a JSON object containing the data you want to display
var data = {
header: 'My video player',
subheader: 'Version 2 coming soon'
}
add that to whatever element you like
const videoplayer = videoPlayerTemplate(data);
document.getElementById('myRandomElement').insertAdjacentHTML("afterbegin", videoplayer);
You can read more about string literals here
edit: HTML import is now deprecated.
Now with Web Components you can inject HTML using an HTML import.
The syntax looks like this:
<link rel="import" href="component.html" >
This will just load the content of the html file in the href attribute inline in the order it appears. You can any valid html in the loaded file, so you can even load other scripts if you want.
To inject that from JavaScript you could do something of the likes of:
var importTag = document.createElement('link');
importTag.setAttribute('rel', 'import');
importTag.setAttribute('href', 'component.html');
document.body.appendChild(importTag);
At the time I am writing this, Chrome and Opera support HTML imports. You can see an up to date compatibility table here http://caniuse.com/#feat=imports
But don't worry about browsers not supporting it, you can use it in them anyway with the webcomponentsjs polyfill.
For more info about HTML imports check http://webcomponents.org/articles/introduction-to-html-imports/
If you don't need any validation for your syntax (which is what makes createElement() so nice) then you could always default to simply setting the innerHTML property of the element you want to insert your markup inside of.
Personally, I would stick with using createElement(). It is more verbose but there are far less things to worry about that way.
If performance is a concern, stay away from innerHTML. You should create the whole object tree using document.createElement() as many times as needed, including for nested elements.
Finally, append it to the document with one statement, not many statements.
In my informal testing over the years, this will give you the best performance (some browsers may differ).
If HTML is ever declared in a variable, it should be simple and for a very specific purpose. Usually, this is not the right approach.
here's 2 possible cases :
Your HTML is static
Your HTML is dynamic
solution 1
In this case, wrap your HTML in double quotes, make it a string and save it in a variable. then push it inside HTML, here's a demo 👇
HTML
<div id="test"></div>
JavaScript
let selector = document.querySelector("#test");
let demo_1 = "<div id='child'> hello and welcome</div>"
selector.innerHTML = demo_1;
solution 2
In this case, wrap your HTML in back ticks, make it a template literal and save it in a variable. then push it inside HTML,
here, you can use variables to change your content. here's a demo 👇
HTML
<div id="test"></div>
JavaScript
let selector = document.querySelector("#test");
let changes = 'hello and welcome'
let demo_1 = `<div id='child'>${changes}</div>`
selector.innerHTML = demo_1;
You can concatenate raw HTML strings (being careful to escape text and prevent XSS holes), or you can rewrite jQuery (or something similar)
I have a situation where I pass text into a third party library, but if my model isPrivate, I'd like to add an element to the text.
return { id: item.id, text: (item.isPrivate == true) ? "<i class=\"icon-lock\" title=\"Private group.\"></i> " + item.label : item.label };
This creates issues with the way the third party library builds up its markup.
This is never a good idea, but third party libraries are there so that we don't have to write everything ourselves. In a situation like this, you have to rely on passing markup though javascript.
When i find a proper solution to this, I will give you an update

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