Develop Reference

How to get class name of element has specific text using javascript/jquery?

I need a JavaScript or jQuery way of extracting the Class name of DIV element by the text it contains.
Let's illustrate. If I had let's say following code:
<div class="_className">UniqueText</div>
I need to to know how to programmatically do something like this:
getClassNameWhereText("UniqueText");
In this case output should be:
_className
Is there a way to do this?

JQuery :contains selector select element has specific text but it isn't exact. For example
$("div:contains(UniqueText)")
Select both of bottom divs
<div class="_className">UniqueText</div>
<div class="_className2">UniqueText2</div>
You can use .filter() to filter selected element by text.
var className = $("*").filter(function(){
return $(this).text() == "UniqueText";
}).attr("class");
var className = $("*").filter(function(){
return $(this).text() == "UniqueText";
}).attr("class");
console.log(className);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="_className">UniqueText</div>
<div class="_className2">UniqueText2</div>

By getting all the div with each function you can search through all the divs and place a condition in which you the value of the div is equal to the particular text that you want to find. Then get the class name by using .attr('class').
$( "div" ).each(function(){
if($(this).text() == "UniqueText"){
var output = $(this).attr('class');
$(".output").html(output);
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="_classname">UniqueText</div>
<div class="output"></div>
It might be a bit long for a code but it gets the work done nicely. :)

You can use :contains(word)
var className = $( "div:contains('John')" ).attr("class");
console.log(className)
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="foo">John Resig</div>
<div class="bar">George Martin</div>
<div class="foo">Malcom John Sinclair</div>
<div class="baz">J. Ohn</div>

You can keep an id for your div, as per your information your text will be unique.
<div id="UniqueText" class="_className">UniqueText</div>
and the js code will be
function getClassNameWhereText(text){
var className = $('#'+text).attr('class');
console.log(className);
}
UPDATE : if you want to using contains
then you can do this,
function getClassNameWhereText(text){
var val = document.getElementById(text).value;
if(text.indexOf(val)>=0){
var className = $('#'+text).attr('class');
console.log(className);
}
}

This should be faster than using jQuery (but a bit more to type):
var xpath = "//div[text()='UniqueText']";
var result = document.evaluate(xpath,
document, null, XPathResult.FIRST_ORDERED_NODE_TYPE);
var node = result.singleNodeValue;
if (node) {
console.log(node.className);
} else {
console.error("Not found!");
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="_className">UniqueText</div>
The reason is, browser's CSS selectors don't support :contains selector, and jQuery needs to emulate it by checking every node matching the rest of the selector. Ditto for using .filter. But XPath is done natively by the browser.
You also cannot specify exact match using the jQuery :contains, like here. If substring matching was indeed needed, you can change the XPath:
var xpath = "//div[contains(text(),'UniqueText')]";
XPath is very powerful, but a bit finicky and largely unknown, so I find it is very under-utilised, even when its use would be a perfect fit.

Jquery assign second child attribute

Is there a way to assign nested div attribute with variable? Like
<div>
<div>
123456
</div>
</div>
Become
<div>
<div sectionid="123">
123456
</div>
</div>
BTW above component will be created by JavaScript.
I've tried something like this, but it didn't work.
var a = $('<div><div>123456</div></div>');
a.eq(":nth-child(2)").attr("sectionid", "123");

Try this snippet.
//FOR DOM HTML
console.log("FOR DOM HTML");
//1st way
$('#input > div').find('div').attr("sectionid","123");
console.log($('#input').html());
//2nd way
$('#input > div > div').attr("sectionid","321");
console.log($('#input').html());
//JS HTML
console.log("FOR JS OBJECT");
var input = $('<div><div>123456</div></div>');
//1st way
input.eq(0).children().attr('sectionid', '456');
console.log(input[0].outerHTML);
var input = $('<div><div>123456</div></div>');
//2nd way
$(input[0]).children().attr('sectionid', '789');
console.log(input[0].outerHTML);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="input">
<div>
<div>
123456
</div>
</div>
</div>

nth-child(2) maches elements that are the second child element of their parent. This is not the case for your div, it is the first element of the parent div.
.eq finds an element at a specific index. It is not the place to pass a selector.
The child selector, >, will find a child element, i.e. div>div will find a div that is an immediate child of a div.
Note that the code you've provided, $('<div></div>123456<div></div>');, doesn't create a DOM tree like the one you've pasted.
Update, now that the code is edited, the value of a is a div with a child div. Since a.find will perform a search within a, you don't have to use a child selector, but can find the div immediately:
a.find('div')

Just apply attribute to children. No complicated 'find', eq(), etc.
var a = $('<div><div>123456</div></div>');
a.children().attr('sectionid', '123');
$('body').append(a);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Why don't you add it in the first place? Not clear if you add it later!
$(document).ready(function() {
var sectionid = "123";
var a = $('<div><div sectionid="' + sectionid + '">123456</div></div>');
$('body').append(a);
});
div[sectionid]{
color: red;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Try this - I have added comments to the code to explain what is happening.
Inspect the element to see that the attribute is added
var a = $('<div><div>123456</div></div>'); // change this to match the structure you want
a.children() // .children gets the direct descendant (which should be the nested div
.eq(0) // gets the first in the array that is returned (if there are multiple direct descendents) - it is a 0 based index selector
.attr('sectionid', '123');
$('body').append(a)
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
More information about .children()
More information about .eq()

try it :
$(document).ready(function(){
$("div").eq(1).attr("sectionid","123");
})

How can I remove content like from an element?

I have a div where the content looks like this:
<div class="container">
<div class="eventSpot bg-blue"></div>
<div class="eventSpot bg-blue"></div>
<div class="eventSpot bg-red"></div>
</div>
The is causing some styling problems so I need to remove it.
How can I remove just that part of the content with jQuery/javascript?

Using jQuery:
var div = $('div.container');
div.html(div.html().replace(/^\s* /m, ''));

I prefer working with nodes instead of html as a string if possible, so I would suggest something like this:
http://jsfiddle.net/p7v89/
$('.container').contents().filter(function() {
return this.nodeType == 3
}).remove();
That will find all text nodes and remove them.

you will get the text without HTML tag and &nbsp etc
This is a solution for HTML tag and &nbsp etc and you can remove and add conditions
convertHtmlToText(passHtmlBlock)
{
str = str.toString();
return str.replace(/<[^>]*(>|$)| |‌|»|«|>/g, ' ');
}

You could alternatively try the .detach() method.
var $data = $('.container > div').detach();
$('.container').empty().html($data);

Collapse HTML if no content found

I want to be able to remove HTML elements if they contain no content.
Let's say we have some markup and are targeting all 'collapse' classes:
<div class='collapse'>[CONTENT?]</div>
If there is some content then don't do anything.
But if there is no content - no string characters or whitespace - then remove the div element completely.
This is easy to implement in the simple cases but with nested content it's slightly more more tricky.
Here is a demo, if you try removing the [CONTENTX?] strings and then seeing what the HTML structure is you'll notice that it doesn't work completely.
If a div only has other divs with no content then that should be treated as no characters or whitespace.
If we remove all [CONTENTX?] strings then we should see no HTML structure.
What ways are there to handle this?
jsFiddle: http://jsfiddle.net/97udq/
HTML:
<div id='container'>
<div class='collapse'>
[CONTENT1?]
</div>
<div class='collapse'>
[CONTENT2?]
<div class='collapse'>
[CONTENT3?]
<div class='collapse'>[CONTENT4?]</div>
<div class='collapse'>[CONTENT5?]</div>
</div>
</div>
</div>
Javascript:
$(function(){
// function
collapse();
// Show HTML structure
alert($('#container').html());
});
function collapse(){
// Loop thru all collapse elements
$('.collapse').each(function(){
// Check for pure whitespace
if($(this).html().replace(/\s+/g, '').length==0){
// Nothing to see, so remove.
$(this).remove();
}
});
}
CSS:
.collapse{
height:20px;
border:1px solid red;
}

I think this does the job;
It just uses text() instead of html();
Here's the documentation.
This one adds the trim(), but I thik that's not what you want.
function collapse(){
$('.collapse').each(function(){
if($(this).text().length==0){
$(this).remove();
}
});
}

Here's another way of accomplishing what you want. It recurses down the DOM pruning nodes from the bottom up. Hope this helps.
function prune(root) {
$.each($(root).children(), function(){
prune($(this));
});
if($(root).html().replace(/\s+/g, '').length==0 && $(root).hasClass("collapse")){
$(root).detach();
}
}
Code integrated into your JSFiddle

You need to recreate the .each() loop, but reversed. Just like that :
function collapse(){
var el = $('.collapse');
for(var i = el.length - 1; i >= 0; i--){
if(el[i].innerHTML.replace(/\s+/g, '').length==0){
$(el[i]).remove();
}
}
}
It will remove the childrens first, then check for parent.
Here a fiddle : http://jsfiddle.net/97udq/5/
EDIT :
I missunderstood your question, here's the right solution :
function collapse(){
$('.collapse').each(function(){
var $this = $(this)
var clone = $this.clone();
clone.children().remove();
if(clone.html().replace(/\s+/g, '').length==0){
$this.children().appendTo($this.parent());
$this.remove()
}
})
}
Basicly, you clone the current div, remove its children and then check if there is some text. If there's none, you append his children to his parent
Fiddle : http://jsfiddle.net/97udq/9/

jQuery comment/uncomment <!--element-->

I am looking for a way to wrap, with jQuery, an element into a comment, like:
<!--
<div class="my_element"></div>
-->
and also a way to remove the comments.
Is this possible?

To wrap an element with comment, or more specifically to replace an element with a comment node having that element's HTML:
my_element_jq = $('.my_element');
comment = document.createComment(my_element_jq.get(0).outerHTML);
my_element_jq.replaceWith(comment);
To switch it back:
$(comment).replaceWith(comment.nodeValue);
If you don't have the reference to the comment node then you need to traverse the DOM tree and check nodeType of each node. If its value is 8 then it is a comment.
For example:
<div id="foo">
<div>bar</div>
<!-- <div>hello world!</div> -->
<div>bar</div>
</div>
JavaScript:
// .contents() returns the children of each element in the set of matched elements,
// including text and comment nodes.
$("#foo").contents().each(function(index, node) {
if (node.nodeType == 8) {
// node is a comment
$(node).replaceWith(node.nodeValue);
}
});

You can comment the element out by doing the following:
function comment(element){
element.wrap(function() {
return '<!--' + this.outerHTML + '"-->';
});
}
DEMO:
http://jsfiddle.net/dirtyd77/THBpD/27/

I'm impresed nobody gave the following solution. The following solution require a container. This container will have inside, the commented / uncommented code.
function comment(element) {
element.html('<!--' + element.html() + '-->')
}
function uncomment(element) {
element.html(element.html().substring(4, element.html().length - 3))
}
function isCommented(element) {
return element.html().substring(0, 4) == '<!--';
}
Example: https://jsfiddle.net/ConsoleTVs/r6bm5nhz/

For wrapping?
function wrap(jQueryElement){
jQueryElement.before("<!--").after("-->");
}
Not sure how successful you'd be finding the comments once wrapped though. A text search on the body element using regular expressions is an option.
Or this - is it possible to remove an html comment from dom using jquery