There are two similar classes - 'item' and 'item one'
When I use document.getElementsByClassName('item') it returns all elements that match both classes above.
How I can get elements with 'item' class only?
The classname item one means the element has class item and class one.
So, when you do document.getElementsByClassName('item'), it returns that element too.
You should do something like this to select the elements with only the class item:
e = document.getElementsByClassName('item');
for(var i = 0; i < e.length; i++) {
// Only if there is only single class
if(e[i].className == 'item') {
// Do something with the element e[i]
alert(e[i].className);
}
}
This will check that the elements have only class item.
Live Demo
document.querySelectorAll('.item:not(.one)');
(see querySelectorAll)
The other way is to loop over the what document.getElementsByClassName('item') returns, and check if the one class is present (or not):
if(element.classList.contains('one')){
...
}
You're going to want to make your own function for exact matches, because spaces in a class means it has multiple classes. Something like:
function GetElementsByExactClassName(someclass) {
var i, length, elementlist, data = [];
// Get the list from the browser
elementlist = document.getElementsByClassName(someclass);
if (!elementlist || !(length = elementlist.length))
return [];
// Limit by elements with that specific class name only
for (i = 0; i < length; i++) {
if (elementlist[i].className == someclass)
data.push(elementlist[i]);
}
// Return the result
return data;
} // GetElementsByExactClassName
You can use Array.filter to filter the matched set to be only those with class test:
var elems = Array.filter( document.getElementsByClassName('test'), function(el){
return !!el.className.match(/\s*test\s*/);
});
Or only those with test but not one:
var elems = Array.filter( document.getElementsByClassName('test'), function(el){
return el.className.indexOf('one') < 0;
});
(Array.filter may work differently depending on your browser, and is not available in older browsers.) For best browser compatibility, jQuery would be excellent for this: $('.test:not(.one)')
If you have jQuery, it can be done using the attribute equals selector syntax like this: $('[class="item"]').
If you insist on using document.getElementsByClassName, see the other answers.
Related
I have a list of elements, and I want to check whether at least one has the class demo_control
The following code works. Is there a more elegant way?
var a='f_date1,f_date2,f_date3,f_date4,f_field1,f_field2'.split(',');
var flag=false;
var i;
for (i = 0; i < a.length; i++) {
if ($('#'+a[i]).hasClass('demo_control')) {
flag=true;
}
}
The documentation of hasClass says:
Determine whether any of the matched elements are assigned the given class.
So no need to loop explicitly; just select the elements in one go, and apply the method on that selection:
let flag = $('#f_date1,#f_date2,#f_date3,#f_date4,#f_field1,#f_field2').hasClass('demo_control');
This could be a possible elegant solution
const ids = 'f_date1,f_date2,f_date3,f_date4,f_field1,f_field2';
const query = ids.split(',').map(el => `#${el}.demo_control`).join(', ');
const flag = $(query).length > 0;
What I've done is just created a single selector for you ids with class. And check if there are any elementa matching this selector.
If demo_control is unique to these fields, why not do:
flag = $(".demo_control").length > 0
This is all you need to do to get a class count...
flag=document.getElementsByClassName('demo_control').length>0;
I'm creating a button that I should highlight certain words within a specified class, but I am having issues with it returning all elements within the class. It will only work if I specify an index, so I'm assuming there may be something wrong with the existing "for loop". Any help is appreciated!
This will work, but only "highlights" the first element in the class, of course:
var bodyText = document.getElementsByClassName('test')[0].innerHTML;
for (var i = 0; i < searchArray.length; i++) {
bodyText = doHighlight(bodyText, searchArray[i], highlightStartTag,
highlightEndTag);}
document.getElementsByClassName('test')[0].innerHTML = bodyText;
return true;
This will not work at all:
var bodyText = document.getElementsByClassName('test').innerHTML;
for (var i = 0; i < searchArray.length; i++) {
bodyText = doHighlight(bodyText, searchArray[i], highlightStartTag,
highlightEndTag);}
document.getElementsByClassName('test').innerHTML = bodyText;
return true;
If you want to replace multiple words in multiple elements, you need two loops:
const testElements = document.getElementsByClassName('test');
for (const element of testElements) {
for (const search of searchArray) {
element.innerHTML = doHighlight(element.innerHTML, search, highlightStartTag, highlightEndTag);
}
}
As you can see getElementsByClassName is pluralized (Elements). Indeed a same class can be assigned to multiple HTML elements. You won't find any way to ommit the [0] and you shouldn't anyway as it might mean you're getting data from the wrong node. If you need data from a specific element that you can ensure is unique then you need to give it an id and use getElementById instead.
You cannot access innerHTML in something which returns an htmlcollection
document.getElementsByClassName('test').innerHTML
Because it's written in plain english: getElementsByClassName. plural.
"Elements".
with an "s" at the end...
meaning it's a (sort of) Array (an htmlcollection)
I need to use native Javascript and for some of these I need to select more than one attribute (ex. a div with a class and id). Here is a code sample of what I've got so far. The example has all single selections.
var $ = function (selector) {
var elements = [];
var doc = document, i = doc.getElementsByTagName("div"),
iTwo = doc.getElementById("some_id"), // #some_id
iThree = doc.getElementsByTagName("input"),
// ^ Lets say I wanted to select an input with ID name as well. Should it not be doc.getElementsByTagName("input").getElementById("idname")
iFour = doc.getElementsByClassName("some_class"); // some_class
elements.push(i,iTwo,iThree,iFour);
return elements;
};
Oh yes, I forgot to mention I cannot use querySelector at all...
It depends on the properties you want to select on. For example, you might pass an object like:
{tagname: 'div', class: 'foo'};
and the function might be like:
function listToArray(x) {
for (var result=[], i=0, iLen=x.length; i<iLen; i++) {
result[i] = x[i];
}
return result;
}
function getByProperties(props) {
var el, elements;
var baseProps = {id:'id', tagName:'tagName'};
var result = [];
if ('tagName' in props) {
elements = listToArray(document.getElementsByTagName(props.tagName));
} else if ('id' in props) {
elements = [document.getElementById(props.id)];
}
for (var j=0, jLen=elements.length; j<jLen; j++) {
el = elements[j];
for (var prop in props) {
// Include all with tagName as used above. Avoids case sensitivity
if (prop == 'tagName' || (props.hasOwnProperty(prop) && props[prop] == el[prop])) {
result.push(el);
}
}
}
return result;
}
// e.g.
getByProperties({tagName:'div', className:'foo'});
However it's a simplistic approach, it won't do things like child or nth selectors.
You can perhaps look at someone else's selector function (there are a few around) and follow the fork to support non–qSA browsers. These are generally based on using a regular expression to tokenise a selector, then apply the selector manually similar to the above but more extensivly.
They also allow for case sensitivity for values (e.g. tagName value) and property names to some extent, as well as map HTML attribute names to DOM property names where required (e.g. class -> className, for -> htmlFor, etc.).
I need to get the ID of an element but the value is dynamic with only the beginning of it is the same always.
Heres a snippet of the code.
<form class="form-poll" id="poll-1225962377536" action="/cs/Satellite">
The ID always starts with poll- then the numbers are dynamic.
How can I get the ID using just JavaScript and not jQuery?
You can use the querySelector for that:
document.querySelector('[id^="poll-"]').id;
The selector means: get an element where the attribute [id] begins with the string "poll-".
^ matches the start
* matches any position
$ matches the end
jsfiddle
Try this.
function getElementsByIdStartsWith(container, selectorTag, prefix) {
var items = [];
var myPosts = document.getElementById(container).getElementsByTagName(selectorTag);
for (var i = 0; i < myPosts.length; i++) {
//omitting undefined null check for brevity
if (myPosts[i].id.lastIndexOf(prefix, 0) === 0) {
items.push(myPosts[i]);
}
}
return items;
}
Sample HTML Markup.
<div id="posts">
<div id="post-1">post 1</div>
<div id="post-12">post 12</div>
<div id="post-123">post 123</div>
<div id="pst-123">post 123</div>
</div>
Call it like
var postedOnes = getElementsByIdStartsWith("posts", "div", "post-");
Demo here: http://jsfiddle.net/naveen/P4cFu/
querySelectorAll with modern enumeration
polls = document.querySelectorAll('[id ^= "poll-"]');
Array.prototype.forEach.call(polls, callback);
function callback(element, iterator) {
console.log(iterator, element.id);
}
The first line selects all elements in which id starts ^= with the string poll-.
The second line evokes the enumeration and a callback function.
Given that what you want is to determine the full id of the element based upon just the prefix, you're going to have to do a search of the entire DOM (or at least, a search of an entire subtree if you know of some element that is always guaranteed to contain your target element). You can do this with something like:
function findChildWithIdLike(node, prefix) {
if (node && node.id && node.id.indexOf(prefix) == 0) {
//match found
return node;
}
//no match, check child nodes
for (var index = 0; index < node.childNodes.length; index++) {
var child = node.childNodes[index];
var childResult = findChildWithIdLike(child, prefix);
if (childResult) {
return childResult;
}
}
};
Here is an example: http://jsfiddle.net/xwqKh/
Be aware that dynamic element ids like the ones you are working with are typically used to guarantee uniqueness of element ids on a single page. Meaning that it is likely that there are multiple elements that share the same prefix. Probably you want to find them all.
If you want to find all of the elements that have a given prefix, instead of just the first one, you can use something like what is demonstrated here: http://jsfiddle.net/xwqKh/1/
I'm not entirely sure I know what you're asking about, but you can use string functions to create the actual ID that you're looking for.
var base = "common";
var num = 3;
var o = document.getElementById(base + num); // will find id="common3"
If you don't know the actual ID, then you can't look up the object with getElementById, you'd have to find it some other way (by class name, by tag type, by attribute, by parent, by child, etc...).
Now that you've finally given us some of the HTML, you could use this plain JS to find all form elements that have an ID that starts with "poll-":
// get a list of all form objects that have the right type of ID
function findPollForms() {
var list = getElementsByTagName("form");
var results = [];
for (var i = 0; i < list.length; i++) {
var id = list[i].id;
if (id && id.search(/^poll-/) != -1) {
results.push(list[i]);
}
}
return(results);
}
// return the ID of the first form object that has the right type of ID
function findFirstPollFormID() {
var list = getElementsByTagName("form");
var results = [];
for (var i = 0; i < list.length; i++) {
var id = list[i].id;
if (id && id.search(/^poll-/) != -1) {
return(id);
}
}
return(null);
}
You'll probably have to either give it a constant class and call getElementsByClassName, or maybe just use getElementsByTagName, and loop through your results, checking the name.
I'd suggest looking at your underlying problem and figure out a way where you can know the ID in advance.
Maybe if you posted a little more about why you're getting this, we could find a better alternative.
You use the id property to the get the id, then the substr method to remove the first part of it, then optionally parseInt to turn it into a number:
var id = theElement.id.substr(5);
or:
var id = parseInt(theElement.id.substr(5));
<form class="form-poll" id="poll-1225962377536" action="/cs/Satellite" target="_blank">
The ID always starts with 'post-' then the numbers are dynamic.
Please check your id names, "poll" and "post" are very different.
As already answered, you can use querySelector:
var selectors = '[id^="poll-"]';
element = document.querySelector(selectors).id;
but querySelector will not find "poll" if you keep querying for "post": '[id^="post-"]'
If you need last id, you can do that:
var id_list = document.querySelectorAll('[id^="image-"]')
var last_id = id_list.length
alert(last_id)
Is there a way in jQuery to loop through or assign to an array all of the classes that are assigned to an element?
ex.
<div class="Lorem ipsum dolor_spec sit amet">Hello World!</div>
I will be looking for a "special" class as in "dolor_spec" above. I know that I could use hasClass() but the actual class name may not necessarily be known at the time.
You can use document.getElementById('divId').className.split(/\s+/); to get you an array of class names.
Then you can iterate and find the one you want.
var classList = document.getElementById('divId').className.split(/\s+/);
for (var i = 0; i < classList.length; i++) {
if (classList[i] === 'someClass') {
//do something
}
}
jQuery does not really help you here...
var classList = $('#divId').attr('class').split(/\s+/);
$.each(classList, function(index, item) {
if (item === 'someClass') {
//do something
}
});
Why has no one simply listed.
$(element).attr("class").split(/\s+/);
EDIT: Split on /\s+/ instead of ' ' to fix #MarkAmery's objection. (Thanks #YashaOlatoto.)
On supporting browsers, you can use DOM elements' classList property.
$(element)[0].classList
It is an array-like object listing all of the classes the element has.
If you need to support old browser versions that don't support the classList property, the linked MDN page also includes a shim for it - although even the shim won't work on Internet Explorer versions below IE 8.
Here is a jQuery plugin which will return an array of all the classes the matched element(s) have
;!(function ($) {
$.fn.classes = function (callback) {
var classes = [];
$.each(this, function (i, v) {
var splitClassName = v.className.split(/\s+/);
for (var j = 0; j < splitClassName.length; j++) {
var className = splitClassName[j];
if (-1 === classes.indexOf(className)) {
classes.push(className);
}
}
});
if ('function' === typeof callback) {
for (var i in classes) {
callback(classes[i]);
}
}
return classes;
};
})(jQuery);
Use it like
$('div').classes();
In your case returns
["Lorem", "ipsum", "dolor_spec", "sit", "amet"]
You can also pass a function to the method to be called on each class
$('div').classes(
function(c) {
// do something with each class
}
);
Here is a jsFiddle I set up to demonstrate and test http://jsfiddle.net/GD8Qn/8/
Minified Javascript
;!function(e){e.fn.classes=function(t){var n=[];e.each(this,function(e,t){var r=t.className.split(/\s+/);for(var i in r){var s=r[i];if(-1===n.indexOf(s)){n.push(s)}}});if("function"===typeof t){for(var r in n){t(n[r])}}return n}}(jQuery);
You should try this one:
$("selector").prop("classList")
It returns a list of all current classes of the element.
var classList = $(element).attr('class').split(/\s+/);
$(classList).each(function(index){
//do something
});
$('div').attr('class').split(' ').each(function(cls){ console.log(cls);})
Update:
As #Ryan Leonard pointed out correctly, my answer doesn't really fix the point I made my self... You need to both trim and remove double spaces with (for example) string.replace(/ +/g, " ").. Or you could split the el.className and then remove empty values with (for example) arr.filter(Boolean).
const classes = element.className.split(' ').filter(Boolean);
or more modern
const classes = element.classList;
Old:
With all the given answers, you should never forget to user .trim() (or $.trim())
Because classes gets added and removed, it can happen that there are multiple spaces between class string.. e.g. 'class1 class2 class3'..
This would turn into ['class1', 'class2','','','', 'class3']..
When you use trim, all multiple spaces get removed..
Might this can help you too. I have used this function to get classes of childern element..
function getClickClicked(){
var clickedElement=null;
var classes = null;<--- this is array
ELEMENT.on("click",function(e){//<-- where element can div,p span, or any id also a class
clickedElement = $(e.target);
classes = clickedElement.attr("class").split(" ");
for(var i = 0; i<classes.length;i++){
console.log(classes[i]);
}
e.preventDefault();
});
}
In your case you want doler_ipsum class u can do like this now calsses[2];.
Thanks for this - I was having a similar issue, as I'm trying to programatically relate objects will hierarchical class names, even though those names might not necessarily be known to my script.
In my script, I want an <a> tag to turn help text on/off by giving the <a> tag [some_class] plus the class of toggle, and then giving it's help text the class of [some_class]_toggle. This code is successfully finding the related elements using jQuery:
$("a.toggle").toggle(function(){toggleHelp($(this), false);}, function(){toggleHelp($(this), true);});
function toggleHelp(obj, mode){
var classList = obj.attr('class').split(/\s+/);
$.each( classList, function(index, item){
if (item.indexOf("_toggle") > 0) {
var targetClass = "." + item.replace("_toggle", "");
if(mode===false){$(targetClass).removeClass("off");}
else{$(targetClass).addClass("off");}
}
});
}
Try This. This will get you the names of all the classes from all the elements of document.
$(document).ready(function() {
var currentHtml="";
$('*').each(function() {
if ($(this).hasClass('') === false) {
var class_name = $(this).attr('class');
if (class_name.match(/\s/g)){
var newClasses= class_name.split(' ');
for (var i = 0; i <= newClasses.length - 1; i++) {
if (currentHtml.indexOf(newClasses[i]) <0) {
currentHtml += "."+newClasses[i]+"<br>{<br><br>}<br>"
}
}
}
else
{
if (currentHtml.indexOf(class_name) <0) {
currentHtml += "."+class_name+"<br>{<br><br>}<br>"
}
}
}
else
{
console.log("none");
}
});
$("#Test").html(currentHtml);
});
Here is the working example: https://jsfiddle.net/raju_sumit/2xu1ujoy/3/
For getting the list of classes applied to element we can use
$('#elementID').prop('classList')
For adding or removing any classes we can follow as below.
$('#elementID').prop('classList').add('yourClassName')
$('#elementID').prop('classList').remove('yourClassName')
And for simply checking if the class is present or not we can use hasClass
I had a similar issue, for an element of type image. I needed to check whether the element was of a certain class. First I tried with:
$('<img>').hasClass("nameOfMyClass");
but I got a nice "this function is not available for this element".
Then I inspected my element on the DOM explorer and I saw a very nice attribute that I could use: className. It contained the names of all the classes of my element separated by blank spaces.
$('img').className // it contains "class1 class2 class3"
Once you get this, just split the string as usual.
In my case this worked:
var listOfClassesOfMyElement= $('img').className.split(" ");
I am assuming this would work with other kinds of elements (besides img).
Hope it helps.
javascript provides a classList attribute for a node element in dom. Simply using
element.classList
will return a object of form
DOMTokenList {0: "class1", 1: "class2", 2: "class3", length: 3, item: function, contains: function, add: function, remove: function…}
The object has functions like contains, add, remove which you can use
A bit late, but using the extend() function lets you call "hasClass()" on any element, e.g.:
var hasClass = $('#divId').hasClass('someClass');
(function($) {
$.extend({
hasClass: new function(className) {
var classAttr = $J(this).attr('class');
if (classAttr != null && classAttr != undefined) {
var classList = classAttr.split(/\s+/);
for(var ix = 0, len = classList.length;ix < len;ix++) {
if (className === classList[ix]) {
return true;
}
}
}
return false;
}
}); })(jQuery);
The question is what Jquery is designed to do.
$('.dolor_spec').each(function(){ //do stuff
And why has no one given .find() as an answer?
$('div').find('.dolor_spec').each(function(){
..
});
There is also classList for non-IE browsers:
if element.classList.contains("dolor_spec") { //do stuff