Using getAttribute with addEventListener in Javascript - javascript

In javascript I create some html to display 5 game characters in a div class named 'characters':
var element = document.getElementsByClassName('characters');
for(var i in characters){
// build the character list
element[0].innerHTML += '<div class="char-container"><img
src="'+characters[i].img.default+'" alt="'+characters[i].name+'">
<h2>'+characters[i].name+'</h2><span class="type '+characters[i].type+'">
</span></div>';
}
In Javascript I add a click event that i want to return the game character name:
var element = document.querySelectorAll ('.characters, .char-container');
let index = 0;
console.log ("element "+element.length);
for( index=0; index < element.length; index++ ) {
clickerFn = function(){
var attribute = (this).getAttribute('h2');
alert("Hello World! +name "+attribute);
}
element[index].addEventListener('click', clickerFn, false);
} // for
This returns a null :-(
Question: in Javascript how do I use getAttribute to get 'character.name' ( what's contained in
Thanks
steve

You can't. h2 is not an attribute. <h2> is an element.
this.querySelector('h2').textContent;
See also:
Attribute
Element
querySelector
type selectors
textContent

Related

Overriding constructor of Element interface in JavaScript

I would like to set id attributes for all the DOM elements by default. The IMPORTANT point is that it should happen during the construction of elements (when the browser is parsing HTML code and creating HTML elements and before appending them to the DOM tree). For example, if the HTML code of my website is like this:
<html>
<head>
<script>
//overriding constructor of Element
</script>
</head>
<body>
<p id='nH6Rf72Jk'> This is a paragraph </p>
<p> This is another paragraph </p>
</body>
</html>
I would like to have an id attribute (a random value) even for elements that do not explicitly an id has specified for them. I think it might be possible by overriding constructor of the Element interface (by the script that exists in the head). In other words, while browser is generating the elements and appending them to the DOM tree, check the id attribute; if it doesn't exist, generate a random value and set it as the id. Does anyone know if is possible to override the Element constructor? Or is there any other solution for this problem?
This should work
let all = document.getElementsByTagName("*");
for (let i=0; i < all.length; i++) {
if(all[i].getAttribute('id') === null){
all[i].setAttribute('id', makeId(6));
}
}
function makeId(length) {
let finalStr = '';
let chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
var charsLength = chars.length;
for (i = 0; i < length; i++ ) {
finalStr += chars.charAt(Math.floor(Math.random() * charsLength));
}
return finalStr;
}
document.addEventListener('DOMContentLoaded', () => {
let elements = document.querySelectorAll('body *');
elements.forEach((elem => {
if (!elem.getAttribute('id')) {
elem.setAttribute('id', btoa(window.crypto.getRandomValues(new Uint32Array(1))[0]));
}
}));
});

How can I list the contents of all the <p> elements in the console using JavaScript?

I'm trying to log the content of all the <p> elements in the console by pressing on a button here is the code so far.
window.addEventListener("load",init);
function init(){
var b = document.getElementById("btn2")
b.addEventListener("click",action)
}
function action(){
var i, items = document.qetElementsByTagName("p");
for (i = 0; i < items.length; i++) {
console.log(items[i]);
}
}
Get content using innerHTML or textContent property
console.log(items[i].innerHTML);
//or
console.log(items[i].textContent);
(Plain JavaScript)
To list all "p" use
console.log(document.getElementsByTagName("p"))
Or use for first "p" only
//console.log(document.getElementsByTagName("p")[0])
To get content of first "p"
console.log(document.getElementsByTagName("p")[0].textContent)

JavaScript get textContent excluding children

First, I'm creating a library for JavaScript and I can not use jQuery. I'm trying to get the text content of an HTML element without the text contents of its children.
Both attributes innerText and textContent don't give me what needed, please help.
You can solve using DOM API as childNodes and nodeType.
var elChildNode = document.querySelector("#hello").childNodes;
var sChildTextSum = "";
elChildNode.forEach(function(value){
if(value.nodeType === Node.TEXT_NODE) {
console.log("Current textNode value is : ", value.nodeValue.trim());
sChildTextSum += value.nodeValue;
}
});
console.log("All text value of firstChild : ", sChildTextSum);
I created a sample code as above.
https://jsfiddle.net/nigayo/p7t9bdc3/
To get Author's Name from the following element, excluding <span>...:
<div class="details__instructor">
Author's Name<span ng-show="job_title">, Entrepreneur</span>
</div>
use childNodes[0]. For example:
document.querySelector('div.details__instructor').childNodes[0].textContent
Using only JavaScript (you specified you cannot use jQuery), and given that you have provided and know the id for the parent element:
document.getElementById('parent_element_id').childNodes[0].nodeValue;
You can also use .trim() to remove any trailing space characters left behind from the removal of any child element text:
document.getElementById('parent_element_id').childNodes[0].nodeValue.trim();
var mydiv = getElementByID("id");
function Get_text(element) {
var selected = element.cloneNode(true);
var text;
while (selected.firstChild) {
if (selected.firstChild.nodeType == 3) text = selected.firstChild.nodeValue;
selected.removeChild(selected.firstChild);
}
return text;
}
Get_text(mydiv);
I know many good solutions here exist, but none of them actually achieved what I needed (get the textContent of a single node, none of its children), so sharing this for future searchers.
var html = document.getElementsByTagName("*");
for (var i = 0; i < html.length; i++) {
var el = html[i];
for (var j = 0; j < el.children.length; j++) {
var child = el.children[j],
childTextContent = child.innerHTML;
// Remove all children tags, leaving only the actual text of the node.
childTextContent = childTextContent.replace(/\<.*\>.*\<\/.*\>/gmi, "");
// Also remove <img /> type tags.
childTextContent = childTextContent.replace(/\<.*\ \/\>/gmi, "");
console.log(childTextContent);
// Now you can do any type of text matching (regex) on the result.
}
});

Access dynamic generated div id

I have some div ids that are generated dynamicly via php
<div id='a<?php echo $gid?>>
How can I access them in JavaScript? All these divs start with "A" followed by a number.
Is there some kind of search function
getElementById(a*)?
Thanks for any help
No generic JavaScript function for this (at least not something cross browser), but you can use the .getElementsByTagName and iterate the result:
var arrDivs = document.getElementsByTagName("div");
for (var i = 0; i < arrDivs.length; i++) {
var oDiv = arrDivs[i];
if (oDiv.id && oDiv.id.substr(0, 1) == "a") {
//found a matching div!
}
}
This is the most low level you can get so you won't have to worry about old browsers, new browsers or future browsers.
To wrap this into a neater function, you can have:
function GetElementsStartingWith(tagName, subString) {
var elements = document.getElementsByTagName(tagName);
var result = [];
for (var i = 0; i < elements.length; i++) {
var element = elements[i];
if (element.id && element.id.substr(0, subString.length) == subString) {
result.push(element);
}
}
return result;
}
The usage example would be:
window.onload = function() {
var arrDivs = GetElementsStartingWith("div", "a");
for (var i = 0; i < arrDivs.length; i++) {
arrDivs[i].style.backgroundColor = "red";
}
};
Live test case.
In case you choose to use jQuery at some point (not worth for this thing alone) all the above code turns to single line:
$(document).ready(function() {
$('div[id^="a"]').css("background-color", "blue");
});
Updated fiddle, with jQuery.
No, you need a fixed id value for getElementById to work. However, there are other ways to search the DOM for elements (e.g. by CSS classes).
You can use querySelectorAll to get all divs that have an ID starting with a. Then check each one to see if it contains a number.
var aDivs = document.querySelectorAll('div[id^="a"]');
for(var index = 0, len = aDivs.length; index < len; index++){
var aDiv = aDivs[index];
if(aDiv.id.match(/a\d+/)){
// aDiv is a matching div
}
}​
DEMO: http://jsfiddle.net/NTICompass/VaTMe/2/
Well, I question myself why you would need to select/get an element, that has a random ID. I would assume, you want to do something with every div that has a random ID (like arranging or resizing them).
In that case -> give your elements a class like "myGeneratedDivs" with the random ID (if you need it for something).
And then select all with javascript
var filteredResults=document.querySelectorAll(".myGeneratedDivs").filter(function(elem){
....
return true;
});
or use jQuery/Zepto/YourWeaponOfChoice
var filteredResults=$(".myGeneratedDivs").filter(function(index){
var elem=this;
....
return true;
});
If you plan to use jQuery, you can use following jQuery selectors
div[id^="a"]
or
$('div[id^="id"]').each(function(){
// your stuff here
});
You will have to target the parent div and when someone click on child div inside a parent div then you can catch the child div.
<div id="target">
<div id="tag1" >tag1</div>
<div id="tag1" >tag2</div>
<div id="tag1" >tag3</div>
</div>
$("#target").on("click", "div", function() {
var showid = $(this).attr('id');
alert(showid)
});
getElementById() will return the exact element specified. There are many javascript frameworks including jQuery that allow much more powerful selection capabilities. eg:
Select an element by id: $("#theId")
Select a group of elements by class: $(".class")
Select subelements: $("ul a.action")
For your specific problem you could easily construct the appropriate selector.

How to get all elements inside "div" that starts with a known text

I have a div element in an HTML document.
I would like to extract all elements inside this div with id attributes starting with a known string (e.g. "q17_").
How can I achieve this using JavaScript ?
If needed, for simplicity, I can assume that all elements inside the div are of type input or select.
var matches = [];
var searchEles = document.getElementById("myDiv").children;
for(var i = 0; i < searchEles.length; i++) {
if(searchEles[i].tagName == 'SELECT' || searchEles.tagName == 'INPUT') {
if(searchEles[i].id.indexOf('q1_') == 0) {
matches.push(searchEles[i]);
}
}
}
Once again, I strongly suggest jQuery for such tasks:
$("#myDiv :input").hide(); // :input matches all input elements, including selects
Option 1: Likely fastest (but not supported by some browsers if used on Document or SVGElement) :
var elements = document.getElementById('parentContainer').children;
Option 2: Likely slowest :
var elements = document.getElementById('parentContainer').getElementsByTagName('*');
Option 3: Requires change to code (wrap a form instead of a div around it) :
// Since what you're doing looks like it should be in a form...
var elements = document.forms['parentContainer'].elements;
var matches = [];
for (var i = 0; i < elements.length; i++)
if (elements[i].value.indexOf('q17_') == 0)
matches.push(elements[i]);
With modern browsers, this is easy without jQuery:
document.getElementById('yourParentDiv').querySelectorAll('[id^="q17_"]');
The querySelectorAll takes a selector (as per CSS selectors) and uses it to search children of the 'yourParentDiv' element recursively. The selector uses ^= which means "starts with".
Note that all browsers released since June 2009 support this.
Presuming every new branch in your tree is a div, I have implemented this solution with 2 functions:
function fillArray(vector1,vector2){
for (var i = 0; i < vector1.length; i++){
if (vector1[i].id.indexOf('q17_') == 0)
vector2.push(vector1[i]);
if(vector1[i].tagName == 'DIV')
fillArray (document.getElementById(vector1[i].id).children,vector2);
}
}
function selectAllElementsInsideDiv(divId){
var matches = new Array();
var searchEles = document.getElementById(divId).children;
fillArray(searchEles,matches);
return matches;
}
Now presuming your div's id is 'myDiv', all you have to do is create an array element and set its value to the function's return:
var ElementsInsideMyDiv = new Array();
ElementsInsideMyDiv = selectAllElementsInsideDiv('myDiv')
I have tested it and it worked for me. I hope it helps you.
var $list = $('#divname input[id^="q17_"]'); // get all input controls with id q17_
// once you have $list you can do whatever you want
var ControlCnt = $list.length;
// Now loop through list of controls
$list.each( function() {
var id = $(this).prop("id"); // get id
var cbx = '';
if ($(this).is(':checkbox') || $(this).is(':radio')) {
// Need to see if this control is checked
}
else {
// Nope, not a checked control - so do something else
}
});
i have tested a sample and i would like to share this sample and i am sure it's quite help full.
I have done all thing in body, first creating an structure there on click of button you will call a
function selectallelement(); on mouse click which will pass the id of that div about which you want to know the childrens.
I have given alerts here on different level so u can test where r u now in the coding .
<body>
<h1>javascript to count the number of children of given child</h1>
<div id="count">
<span>a</span>
<span>s</span>
<span>d</span>
<span>ff</span>
<div>fsds</div>
<p>fffff</p>
</div>
<button type="button" onclick="selectallelement('count')">click</button>
<p>total element no.</p>
<p id="sho">here</p>
<script>
function selectallelement(divid)
{
alert(divid);
var ele = document.getElementById(divid).children;
var match = new Array();
var i = fillArray(ele,match);
alert(i);
document.getElementById('sho').innerHTML = i;
}
function fillArray(e1,a1)
{
alert("we are here");
for(var i =0;i<e1.length;i++)
{
if(e1[i].id.indexOf('count') == 0)
a1.push(e1[i]);
}
return i;
}
</script>
</body>
USE THIS I AM SURE U WILL GET YOUR ANSWER ...THANKS

Categories