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For loop within a for loop? - Javascript

newbie javascript question. I made sure to research as much as I could before posting here, I've tried many solutions but could be searching for the wrong thing.
I've attached an image below of the issue I have. I'm trying to retrieve everything in the dark blue boxes, but I can't identify those input tags as there is nothing unique about them, I can however identify their parent divs by the class 'f-active'. When the divs have that class they have been selected by the user which is what I am interested in.
My attempt so far
var divArray = document.querySelectorAll('div.add-filter.f-active');
var arr = [];
for(var i=0; i < divArray.length; i++){
var childArray = divArray[i].children;
// console.log(childArray);
for(var i=0; i < childArray.length; i++){
if(childArray[i].tagName == "INPUT"){
var catNameCollection = arr.push(childArray[i].name);
// console.log(catNameCollection);
}
}
}
I tried to use a for loop to get all the parents, then use another for loop to select the children (input tags) and then grab the name attribute, however it is just outputing numbers. I did originally try to create 'divArray' as document.querySelectorAll('div.add-filter.f-active').children, but this and then grab the name attribute in the for loop, but this didn't return anything at all.
Any help anyone could offer would be greatly appreciated, I'd love to know what I'm doing wrong.
Thank you!

Your i is same for both loops. Use:
var divArray = document.querySelectorAll('div.add-filter.f-active');
var arr = [];
for(var i=0; i < divArray.length; i++){
var childArray = divArray[i].children;
// console.log(childArray);
for(var k=0; k < childArray.length; k++){
if(childArray[k].tagName == "INPUT"){
var catNameCollection = arr.push(childArray[k].name);
// console.log(catNameCollection);
}
}
}

Classic for-loops usually aren't the best tool for iterating through DOM elements - they add a lot of clutter and are error-prone, especially when you have to nest them.
In your case it'd be simpler to instead modify your query to directly grab all input elements with a div.f-active parent, then extract the names by iterating through them with a forEach. For example (using ES6 or higher):
const arr = [];
// Get list of all <input> elements that have <div> element parents with class f-active.
const nodes = document.querySelectorAll('div.add-filter.f-active > input');
// Extract name from each input element matched by your selector.
nodes.forEach(node => arr.push(node.name));
Or if you're stuck using ES5:
var arr = [];
var nodes = document.querySelectorAll('div.add-filter.f-active > input');
nodes.forEach(function(node) {
arr.push(node.name);
});
Here's a quick JSFiddle I put together to demonstrate the concept for you. (You'll need to open the console to see the result)
Hopefully that helps :)

get the text of a div

I have been trying to get the text from a div using only javascript.
I started with jQuery using the following code:
var divText = $("div.Xr3").html();
Then for my JavaScript I tried:
var divText = document.getElementsByClassName("Xr3").innerHtml;
Which returns undefined. How can I accomplish this using JavaScript only?

getElementsByClassName returns a live array of HTML elements, so you can't access innerHTML directly like this. You will either have to loop over its results, or if you know there's only one, apply [0] to it before accessing innerHTML.
var divTexts = [];
var divs = document.getElementsByClassName("Xr3");
var numDivs = divs.length;
while (var i = 0; i < numDivs; i++) {
divTexts.push(divs[i].innerHtml);
}
or, in a single-element scenario,
var divText = document.getElementsByClassName("Xr3")[0].innerHtml;

If Xr3 is used one time, you can use
var divText = document.getElementsByClassName("Xr3")[0].innerHtml;

How to get all HTML attributes which start with something (the attribute names, *not* their values!)

I would like to get all the elements/nodes in an HTML page which contain attributes that start with something (again, the attribute names start with something, not their values!). For example, TinyMCE has a tendency of adding custom attributes to the elements it saves, like "mce_style", "mce_href", "mce_bogus", etc. I would like to have something like the CSS3 selector for attribute values, [attr^="mce_"], but not for the values, the attribute names.
Of course, I can iterate through all DOM nodes and their attributes and check them one by one, but I was wondering whether there is a more efficient way.
Please don't give me TinyMCE-specific answers, I'm pretty sure there's a flag which would prevent TinyMCE for saving these attributes, but the question is generic.

here's a simple demo to find all elements that contain an attribute starting with mce_. might need some refinements.
function getMCE() {
var el, attr, i, j, arr = [],
reg = new RegExp('^mce_', 'i'), //case insensitive mce_ pattern
els = document.body.getElementsByTagName('*'); //get all tags in body
for (i = 0; i < els.length; i++) { //loop through all tags
el = els[i] //our current element
attr = el.attributes; //its attributes
dance: for (j = 0; j < attr.length; j++) { //loop through all attributes
if (reg.test(attr[j].name)) { //if an attribute starts with mce_
arr.push(el); //push to collection
break dance; //break this loop
}
}
}
return arr;
}
console.log(getMCE())​

Try this:
FUNCTIONS
//custom selector expression
$.extend($.expr[':'],{
attr:function(o,i,m){
var attrs=$.getAttrAll(o),re=m[3],found=false;
$.each(attrs,function(k,v){
if(new RegExp(re).test(v)) { return found=true;}
});
return found;
}
});
// get all atrributes of an element
$.getAttrAll=function(el){
var rect = [];
for (var i=0, attrs=el.attributes, len=attrs.length; i<len; i++){
rect.push(attrs.item(i).nodeName);
}
return rect;
};
`
USAGE
// calling custom selector expression :attr(regexp)
$(function(){
$('body').find(':attr("^mce_")').css({background:'yellow'});
});
HTML
<body>
<p mce_style="height:50px" id="x" data-hello="hello">selected</p>
<div not_mce_bogus="abc">not_mce_bogus</div>
<div mce_href="http://rahenrangan.com">selected</div>
<p>othrs</p>
</body>

One option, if you don't mind temporarily altering your DOM, is to extract your HTML into a string and search for the attributes via RegExp. When you find the attributes, you could append a "needle" in the DOM so that you can use jQuery to select the elements.
Here is a working concept (run with console open):
http://jsfiddle.net/skylar/N43Bm/
Code:
$.fn.extend({
findAttributes: function(attribute) {
var attributeFinder = new RegExp(attribute + '(.+)="', "gi");
var elementHTML = this.html().replace(attributeFinder, "data-needle='pin' "+attribute+"$1=\"");
this.html(elementHTML);
return this.find("[data-needle=pin]").removeAttr('data-needle');
}
});
console.log($("body").findAttributes('mce_'));
Note: my regexp is not great. You'll have to take better care than I have in this example.

Try this: (I tried putting * instead of a tag but it colored all the elements including those who do not have mce_style attribute as well)
a[mce_style] { color : red; }​
Demo : http://jsfiddle.net/Tcdmb/
More info : https://developer.mozilla.org/en/CSS/Attribute_selectors

Splitting classes & matching them against another DIV. JQuery

I have a div named box which contains three classes. I want to create a variable named relatedBoxes that stores the check boxes that share any of the same classes that box has.
I am splitting up the classes and storing them in the variable named splitClass.
I now just need the method to see whether :checkbox contains any of the classes saved within splitClass. I have tried by creating the variable relatedBoxes but this doesn't quite work.
The markup:
<div id="box" class="marker blue large">
The JavaScript:
var c = $('#box').attr('class');
var splitClass = c.split(' ');
var relatedBoxes = $(':checkbox').hasClass(splitClass);
Thanks a lot guys

hasClass expect a single class name, you're passing it an array right now. If you're trying to find all elements with marker, blue or large, something like:
var relatedBoxes = $( ':checkbox' ).filter( '.' + splitClass.join( ',.' ) );

You can use .filter() [docs] and iterate over the classes of the element:
var splitClass = $('#box').attr('class').split(' ');
var relatedBoxes = $('input[type="checkbox"]').filter(function() {
for(var i = 0, len = splitClass.length; i < len; i++) {
if($(this).hasClass(splitClass[i])) return true;
}
return false;
});

Javascript get text inside a <span> element

I need to get the text that is inside a element.
I can only grab the class of this element and NOT the ID.
<span class="fileName">test.png</span>
So I need a way to get test.png, but as you see I have only the class of the element and not the ID.
Just notice also that we may have more <span class="fileName"></span>, so it could look like this
<span class="fileName">test1.png</span>
<span class="fileName">test2.png</span>
<span class="fileName">test3.png</span>
<span class="fileName">test4.png</span>
In the case we have more, like the example above, I need to get ALL the values and not only one, because I need to pass this value to another page with jQuery. So it should be able to get one value or more from that element.
Please help!
And also I am not a javascript expert!

var filenames = $('.fileName').map(function(){
return $(this).text();
}).get();
The array filenames will contain all the names of the images. You can pass on this array to another jQuery function, or anywhere else you like to do so.
You can test it here »
Update
Since you request the filenames to be a string separated by a comma, you can do it like this:
var filenames = $('.fileName').map(function(){
return $(this).text();
}).get().join(',');
Now, filenames will contain the string test1.png,test2.png,test3.png,test4.png.

Use document.getElementsByClassName: http://jsfiddle.net/pCswS/.
var elems = document.getElementsByClassName("fileName");
var arr = [];
for(var i = 0; i < elems.length; i++) {
arr.push(elems[i].innerHTML);
}
alert(arr);
(Since you didn't tag the question with jQuery I assume you have to do it with plain JavaScript.)

$('span.fileName').each(function() {
var fileName = $(this).text();
doSomethingWithFileName(fileName);
});
Here the span.fileName selector returns all spans with class fileName then we iterate through, reading the text from each one. You may want to find a container element first and then only iterate inside that, e.g.
var $container = $('#myFileNames');
$container.find('span.fileName').each( ... );

Here's my take:
var spans = document.getElementsByClassName('fileName');
var values = [];
for(var i = 0; i < spans.length; i++) {
values.push(spans[i].innerHTML);
}
// Example of processing: alert the values
alert(values);

Use the following jQuery selector
$("span.fileName").html()