JavaScript possible to select all elements with classname that starts with (...)? [duplicate] - javascript

I'm trying to only show certain divs. The way I have decided to do this is to first hide all elements that start with "page" and then only show the correct divs. Here's my (simplified) code:
<form>
<input type="text" onfocus="showfields(1);">
<input type="text" onfocus="showfields(2);">
</form>
<div class="page1 row">Some content</div>
<div class="page1 row">Some content</div>
<div class="page2 row">Some content</div>
<div class="page2 row">Some content</div>
<script>
function showfields(page){
//hide all items that have a class starting with page*
var patt1 = /^page/;
var items = document.getElementsByClassName(patt1);
console.log(items);
for(var i = 0; i < items.length; i++){
items[i].style.display = "none";
}
//now show all items that have class 'page'+page
var item = document.getElementsByClassName('page' + page);
item.style.display = '';
}
</script>
When I console.log(items); I get a blank array. I'm pretty sure the regexp is right (get all items starting with 'page').
The code I'm using is old school JS, but I'm not adverse to using jQuery. Also if there is a solution that doesn't use regexp, that's fine too as I'm new to using regexp's.

getElementsByClassName only matches on classes, not bits of classes. You can't pass a regular expression to it (well, you can, but it will be type converted to a string, which is unhelpful).
The best approach is to use multiple classes…
<div class="page page1">
i.e. This div is a page, it is also a page1.
Then you can simply document.getElementsByClassName('page').
Failing that, you can look to querySelector and a substring matching attribute selector:
document.querySelectorAll("[class^=page]")
… but that will only work if pageSomething is the first listed class name in the class attribute.
document.querySelectorAll("[class*=page]")
… but that will match class attributes which mention "page" and not just those with classes which start with "page" (i.e. it will match class="not-page".
That said, you could use the last approach and then loop over .classList to confirm if the element should match.
var potentials = document.querySelectorAll("[class*=page]");
console.log(potentials.length);
elementLoop:
for (var i = 0; i < potentials.length; i++) {
var potential = potentials[i];
console.log(potential);
classLoop:
for (var j = 0; j < potential.classList.length; j++) {
if (potential.classList[j].match(/^page/)) {
console.log("yes");
potential.style.background = "green";
continue elementLoop;
}
}
console.log("no");
potential.style.background = "red";
}
<div class="page">Yes</div>
<div class="notpage">No</div>
<div class="some page">Yes</div>
<div class="pageXXX">Yes</div>
<div class="page1">Yes</div>
<div class="some">Unmatched entirely</div>

Previous answers contain parts of the correct one, but none really gives it.
To do this, you need to combine two selectors in a single query, using the comma , separator.
The first part would be [class^="page"], which will find all the elements whose class attribute begins with page, this selector is thus not viable for elements with multiple classes, but this can be fixed by [class*=" page"] which will find all the elements whose class attribute have somewhere the string " page" (note the space at the beginning).
By combining both selectors, we have our classStartsWith selector:
document.querySelectorAll('[class^="page"],[class*=" page"]')
.forEach(el => el.style.backgroundColor = "green");
<div class="page">Yes</div>
<div class="notpage">No</div>
<div class="some page">Yes</div>
<div class="pageXXX">Yes</div>
<div class="page1">Yes</div>
<div class="some">Unmatched entirely</div>

You can use jQuery solution..
var $divs = $('div[class^="page"]');
This will get all the divs which start with classname page

$(document).ready(function () {
$("[class^=page]").show();
$("[class^=page]").hide();
});
Use this to show hide div's with specific css class it will show/hide all div's with css class mention.

Related

querySelectorAll for grouped data-attributes

Suppose I have the following markup...
<div data-namespace-title="foo"></div>
<div data-namespace-description="bar"></div>
<div data-namespace-button="foo"></div>
Is there anyway in which I can select of them with a querySelectorAll?
I've tried document.querySelectorAll([data-namespace-*]), but that doesn't work of course
There is no easy way to do it, simply because the browser does not implement wildcard selectors on the attribute name/key (only on its value). What you can do is to simply iterate through your element set (in this case, their common denominator is div), and then filter them out.
You can access the list of attributes of each DOM node by calling <Node>.attributes, and then convert that into an array, and check if one or more of each attribute's name matches the regex pattern /^data-namespace-.*/gi:
var els = document.querySelectorAll("div");
var filteredEls = Array.prototype.slice.call(els).filter(function(el) {
var attributes = Array.prototype.slice.call(el.attributes);
// Determine if attributes matches 'data-namespace-*'
// We can break the loop once we encounter the first attribute that matches
for (var i = 0; i < attributes.length; i++) {
var attribute = attributes[i];
// Return the element if it contains a match, and break the loop
if (attribute.name.match(/^data-namespace-.*/gi))
return el;
}
});
console.log(filteredEls);
<div data-namespace-title="foo">title</div>
<div data-namespace-description="bar">description</div>
<div data-namespace-button="foobar">button</div>
<div data-dummy>dummy</div>
Update: if you're familiar with ES6, it gets a lot cleaner, because:
We can use Array.from in place of the cumbersome Array.prototype.slice.call(...). Pro-tip: you can also use the spread operator, i.e. const els = [...document.querySelectorAll("div")].
We can use Array.some in place of manually creating a for loop with return logic
const els = Array.from(document.querySelectorAll("div"));
const filteredEls = els.filter(el => {
const attributes = Array.from(el.attributes);
return attributes.some(attribute => attribute.name.match(/^data-namespace-.*/gi));
});
console.log(filteredEls);
<div data-namespace-title="foo">title</div>
<div data-namespace-description="bar">description</div>
<div data-namespace-button="foobar">button</div>
<div data-dummy>dummy</div>
Not sure if you would be up for changing the format of you attributes, but making them all the same and adding an extra attribute could be of use if you want to using querySelectorAll
Array.from(document.querySelectorAll('[data-namespace]')).forEach(el => {
console.log(el.getAttribute('data-value'))
})
<div data-namespace="title" data-value="foo"></div>
<div data-namespace="description" data-value="bar"></div>
<div data-ns="button" data-value="foo"></div>
<div data-namespace="button" data-value="foo"></div>
Your other option is to use xpath.
Note: When using iterateNext() it will break if you modify the document before calling it.
var divs = document.evaluate('//#*[starts-with(name(.), "data-namespace")]', document, null, XPathResult.ANY_TYPE, null);
var div = divs.iterateNext()
while (div) {
alert(div.ownerElement.textContent)
div = divs.iterateNext()
}
<div data-namespace-title="foo">Foo</div>
<div data-namespace-description="bar">Bar</div>
<div data-ns-button="foo">NS Foo</div>
<div data-namespace-button="foo">Foo</div>
There's no built-in selector for such a thing, but you can still accomplish it easily enough, by selecting all elements and then filtering for those which have an attribute that starts with data-namespace:
console.log(
[...document.querySelectorAll('*')]
.filter(({ attributes }) =>
[...attributes].some(({ name }) => name.startsWith('data-namespace'))
)
);
<div data-baz="baz"></div>
<div data-namespace-title="foo"></div>
<div data-namespace-description="bar"></div>
<div data-namespace-button="foo"></div>

Can I select classes by order like this?

So I have this HTML here generated by Wordpress. I want to select the DIVs seperately using JS. Is this possible? Can I maybe select them by the order on which JS finds them in my HTML?
I tried if something like this would be possible (By adding an index number) but I believe that is used only for the LI element. But you get the idea. The end result is to add a different classname to each div object using .className
var koffie = document.getElementsByClassName("g-gridstatistic-item-text2")[0];
var brain = document.getElementsByClassName("g-gridstatistic-item-text2")[1];
var tevred = document.getElementsByClassName("g-gridstatistic-item-text2")[2];
console.log(koffie);
console.log(brain);
console.log(tevred);
<div class="g-gridstatistic-wrapper g-gridstatistic-3cols">
<div class="g-gridstatistic-item">
<div class="g-gridstatistic-item-wrapper">
<div class="g-gridstatistic-item-text1 odometer" data-odometer-value="4"></div>
<div class="g-gridstatistic-item-text2">Kopjes koffie per dag</div>
</div>
</div>
<div class="g-gridstatistic-item">
<div class="g-gridstatistic-item-wrapper">
<div class="g-gridstatistic-item-text1 odometer" data-odometer-value="14"></div>
<div class="g-gridstatistic-item-text2">Brainstormsessies per week</div>
</div>
</div>
<div class="g-gridstatistic-item">
<div class="g-gridstatistic-item-wrapper">
<div class="g-gridstatistic-item-text1 odometer" data-odometer-value="12"></div>
<div class="g-gridstatistic-item-text2">Tevreden klanten</div>
</div>
Your JavaScript code is looking for DOM elements before it checks whether the DOM has even loaded. Try wrapping it in an event listener, like so:
JS
document.addEventListener('DOMContentLoaded', function () {
var koffie = document.getElementsByClassName("g-gridstatistic-item-text2")[0];
var brain = document.getElementsByClassName("g-gridstatistic-item-text2")[1];
var tevred = document.getElementsByClassName("g-gridstatistic-item-text2")[2];
//console.log(koffie);
//console.log(brain);
//console.log(tevred);
/* to evidence that targeting works: */
brain.classList.add('addedClass');
});
CSS
.addedClass {
font-size:22px;
color:red;
}
Full demo here:
https://jsbin.com/saxizeyabo/edit?html,css,js,console,output
simply like this
var yourVariableName = document.getElementsByClassName("g-gridstatistic-item-text2");
console.log(youVariableName[0]);
console.log(youVariableName[1]);
and so on like an array
document.querySelectorAll('.g-gridstatistic-item-text2').item(0);
https://developer.mozilla.org/de/docs/Web/API/Document/querySelectorAll
This way, you can just use CSS-Selectors
The below code should work.
var classes = document.getElementsByClassName('g-gridstatistic-item-text2');
for(var i=0; i<=classes.length; i++) {
var appendClass = 'your_class_name'+i;
classes[i].classList.add(appendClass);
}

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.

Apply javascript function to same ids

I just want to ask let say if we have multiple divs with same id how can we display none them using javascript ?
I tried:
<script>
function filterfunc() {
if(document.getElementById('filter_deductible').value == 'id_50'){
document.getElementById('id_0').style.display = 'none';
document.getElementById('id_50').style.display = 'block';
}
}
</script>
And here is my html divs with same ids:
<div id="id_0">0</div>
<div id="id_0">0</div>
<div id="id_50">50</div>
But its hidding only one div of id id_0 instead of all div having id_0
Any suggestions please
Id must be unique, you should use class like,
<div class="id_0">0</div>
<div class="id_0">0</div>
<div class="id_50">50</div>
And to hide all id_0 use
function filterfunc() {
if($('#filter_deductible').val() == 'id_50'){
$('div.id_0').hide();
$('div.id_50').show();
}
}
It simple using jQuery like
HTML
<select name="filter_deductible" id="filter_deductible">
<option value="id_0">0</option>
<option value="id_50">50</option>
</select>
<div id="id_0">0</div>
<div id="id_0">0</div>
<div id="id_50">50</div>
jQuery
$("#filter_deductible").change(function(){
if($(this).val()=="id_50")
{
$('[id="id_0"]').hide();
}
});
Demo
you should use a class in case there are multiple elements. Or use different ids.
Ids are meant to be unique.
<script>
function filterfunc() {
if(document.getElementById('filter_deductible').value == 'id_50'){
$('.id_0').css("display","none")
$('.id_50').css("display","block")
}
}
</script>
<div class="id_0">0</div>
<div class="id_0">0</div>
<div class="id_50">50</div>
Or
<script>
function filterfunc() {
if(document.getElementById('filter_deductible').value == 'id_50'){
$('.id_0').hide()
$('.id_50').css("display","block")
}
}
</script>
<div class="id_0">0</div>
<div class="id_0">0</div>
<div class="id_50">50</div>
Do not do this. Having multiple elements with the same ids leads to undefined behaviour. If you need to attach information to your dome nodes use data attributes or classes.
Notice how getElementById is singular form? It only ever expects to select and return one element.
That being said, you can probably get away with
document.querySelectorAll("#id_0")
if you want to use javascript functions on dom elements you have to use class not id attribute.
id attribute is unique in whole html document.
try to use jquery.
$.(document).ready(function(){
$("#filter_deductible").change(function(){
var $this = $(this); //instance of element where was changed value
if($this.val() == 'id_50'){
$(".id_0").hide();
$(".id_50").show();
}
});
});
your document html should looks like.
<div class="id_0">0</div>
<div class="id_0">0</div>
<div class="id_50">50</div>
this will works only if you will include jquery library inside tags. And your dom element #filter_deductible allows change event trigger.
hope i helped you
Use classes in this case ID is unique.
<div class="zero">0</div>
<div class="zero">0</div>
<div class="class_50">50</div>
you can use jQuery:
$('.zero').hide();
$('.class_50').show();
The HTML spec requires that the ID attribute to be unique in a page:
If you want to have several elements with the same ID your code will not work as the method getElementByID only ever returns one value and ID's need to be unique. If you have two ID's with the same value then your HTML is invalid.
What you would want to do is use div class="id_0" and use the method getElementsByClassName as this returns an Array of elements
function filterFunc() {
var n = document.getElementsByClassName("id_0");
var a = [];
var i;
while(n) {
// Do whatever you want to do with the Element
// This returns as many Elements that exist with this class name so `enter code here`you can set each value as visible.
}
}

Siblings with same attribute value

I have a div structure like
<div>
<div class='class1'>contens</div>
<div class='class2'>contens</div>
<div class='class2'>contens</div>
<div class='class2'>contens</div>
<div class='class3'>contens</div>
<div class='class2'>contens</div>
<div class='class1'>contens</div>
</div>
Here I want to write a selector which will select all the div elements with class='class2', they should be adjacent to each other. i.e I should select only index 1,2,3 but not div index 5 since its not adjacent to group.
Please Help here.
You can use the adjacent sibling selector
var elems = $('.class2 + .class2').add( $('.class2 + .class2').prev() )
FIDDLE
or caching the selector (with an argument to a IIFE)
var elems = (function(x) {return x.add( x.prev() )})($('.class2 + .class2'));
FIDDLE
Here is an alternative solution with .filter:
For example:
$('.class2').filter(function() {
return $(this).prev('.class2').add($(this).next('.class2')).length > 0;
});
It filters out the elements that don't have a sibling with class .class2.

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