Loop works just 16 times instead of 36 - javascript

Hello I am now at black out mode while trying to create this loop
The code is like this :
function finished() {
var summaryDiv = document.createElement("DIV");
summaryDiv.setAttribute("id","summary");
document.getElementById("main_content").appendChild(summaryDiv);
var summaryLabel = document.createElement("P");
summaryLabel.setAttribute("id","score");
document.getElementById("summary").appendChild(summaryLabel);
var radios = document.getElementsByTagName('input');
var value = 0;
for (var i = 0; i < radios.length; i++) {
if (radios[i].type === 'radio' && radios[i].checked && radios[i].value == "true") {
value += 1;
console.log(value);
} else {
console.log(value);
}
document.getElementsByClassName("qcontainer")[i].style.display = "none";
document.getElementById("score").innerHTML = value;
}
}
//The value of radios.length is 36, and it seems like it takes the value only of first 16 radio buttons, it doesnt matter if another 8 radio buttons have value TRUE it always returns only TRUEs from the first 16 radio Buttons, I know it might be a little bit confusing but I don't know what is wrong with this loop.

document.getElementsByTagName returns a live HtmlCollection. This means that when you remove an element from DOM, either through removeChild or by setting innerHTML of a parent the collection is updated.
A possible way to loop over a live HtmlCollection like this is to perform a while on the .length of the collection.
while (radios.length) {
// Use radios[0]
// Remove radios[0] from DOM
}

Related

Find whether all checkbox are checked within a parent div

I am trying to get the state of two input checkboxes within a div element. I need to set a flag variable to true only if both the checkboxes are checked. If any of the input checkbox is unchecked , then it should be set to false.
I tried this using for loop using the below code
var oParNode = oNode.ParentNode;
if (null != oParNode) {
for (var i = 0; i < oNode.ParentNode.Nodes.length; i++) {
if (oNode.ParentNode.Nodes[i].Checked) {
checked = true;
}
else {
checked = false;
}
}
}
In this code , Nodes[i] returns the input element. When I check the first checkbox first and the second one next this loop works fine but when I check the second one first , the checked variable is set to true based on the second checkbox value which is executed at last.
Expected: I need to return "checked" to be true only if both checkboxes are checked .
Can some one suggest me on this.
You can use Array#some() method, to check if there's an unchecked one:
var checked = oNode.ParentNode.Nodes.some(check => !check.checked)
Seems for second node it is overriding the value. If you know there are two checkboxes you can directly check it like this.
if (oNode.ParentNode.Nodes[0].Checked && oNode.ParentNode.Nodes[1].Checked) {
checked = true;
} else {
checked = false;
}
Instead of finding all checked, find unchecked instead since this is what you are looking for.
var checked = true;
for (var i = 0; i < oNode.ParentNode.Nodes.length; i++) {
if (!oNode.ParentNode.Nodes[i].Checked) {
checked = false;
break;
}
}
You need to break your loop in case any of checkbox is not checked
var oParNode = oNode.ParentNode;
if (null != oParNode) {
for (var i = 0; i < oNode.ParentNode.Nodes.length; i++) {
if (oNode.ParentNode.Nodes[i].Checked) {
checked = true;
} else {
checked = false;
break;
}
}
}
You can simply every method of array instead of loop
let checkedAll = oNode.ParentNode.Nodes.every(element => element.checked )

Using querySelectorAll to get ALL elements with that class name, not only the first

I've ditched jquery about 9(ish) months ago and needed a selector engine (without all the hassle and don't mind ie<7 support) so i made a simplified version of document.querySelectorAll by creating this function:
// "qsa" stands for: "querySelectorAll"
window.qsa = function (el) {
var result = document.querySelectorAll(el)[0];
return result;
};
This works perfectly fine for 95% of the time but I've had this problem for a while now and i have researched mdn, w3c, SO and not to forget Google :) but have not yet found the answer as to why I only get the first element with the requested class.
And I know that only the first element being returned is caused by the "[0]" at the end, but the function won't work if I remove it so I've tried to make a for loop with an index variable that increases in value depending on the length of elements with that class like this:
window.qsa = function (el) {
var result, el = document.querySelectorAll(el);
for(var i = 0; i < el.length; ++i) {
result = el[i];
}
return result;
};
Again that did not work so I tried a while loop like this:
window.qsa = function (el) {
var result, i = 0, el = document.querySelectorAll(el);
while(i < el.length) {
i++;
}
result = el[i];
return result;
};
By now I'm starting to wonder if anything works? and I'm getting very frustrated with document.querySelectorAll...
But my stubborn inner-self keeps going and I keep on failing (tiering cycle) so I know that now is REALLY the time to ask these questions :
Why is it only returning the first element with that class and not all of them?
Why does my for loop fail?
Why does my while loop fail?
And thank you because any / all help is much appreciated.
Why is it only returning the first element with that class and not all of them?
Because you explicitly get the first element off the results and return that.
Why does my for loop fail?
Because you overwrite result with a new value each time you go around the end of loop. Then you return the last thing you get.
Why does my while loop fail?
The same reason.
If you want all the elements, then you just get the result of running the function:
return document.querySelectorAll(el)
That will give you a NodeList object containing all the elements.
Now that does what you say you want, I'm going to speculate about what your real problem is (i.e. why you think it doesn't work).
You haven't shown us what you do with the result of running that function, but my guess is that you are trying to treat it like an element.
It isn't an element. It is a NodeList, which is like an array.
If you wanted to, for instance, change the background colour of an element you could do this:
element.style.backgroundColor = "red";
If you want to change the background colour of every element in a NodeList, then you have to change the background colour of each one in turn: with a loop.
for (var i = 0; i < node_list.length; i++) {
var element = node_list[i];
element.style.backgroundColor = "red";
}
You are returning a single element. You can return the array. If you want to be able to act on all elements at once, jQuery style, you can pass a callback into your function;
window.qsa = function(query, callback) {
var els = document.querySelectorAll(query);
if (typeof callback == 'function') {
for (var i = 0; i < els.length; ++i) {
callback.call(els[i], els[i], i);
}
}
return els;
};
qsa('button.change-all', function(btn) {
// You can reference the element using the first parameter
btn.addEventListener('click', function(){
qsa('p', function(p, index){
// Or you can reference the element using `this`
this.innerHTML = 'Changed ' + index;
});
});
});
qsa('button.change-second', function(btn) {
btn.addEventListener('click', function(){
var second = qsa('p')[1];
second.innerHTML = 'Changed just the second one';
});
});
<p>One</p>
<p>Two</p>
<p>Three</p>
<button class='change-all'>Change Paragraphs</button>
<button class='change-second'>Change Second Paragraph</button>
Then you can call either use the callback
qsa('P', function(){
this.innerHTML = 'test';
});
Or you can use the array that is returned
var pList = qsa('p');
var p1 = pList[0];
This loop
for(var i = 0; i < el.length; ++i) {
result = el[i];
}
overwrites your result variable every time. That's why you always get only one element.
You can use the result outside though, and iterate through it. Kinda like
var result = window.qsa(el)
for(var i = 0; i < result.length; ++i) {
var workOn = result[i];
// Do something with workOn
}

select.val returning undefined in array

I'm doing the following:
$('#clear-button').click(function () {
var clearableFieldArray = $('.clearable-field');
var array = Array.prototype.slice.call(clearableFieldArray);
for (var i = 0; i < 7; i++) {
if (i == 6) {
array[i].val('');
} else {
array[i].val('All');
}
}
});
when I do console.log(array[i]) it prints the correct elements and children, however when I try to access the .val() it keeps returning undefined, why is it doing that
You can wrap $(array[i]) with the jQuery selector because it looks like you are not selecting a jQuery object but a regular DOM object.
if its one of the first 6 elements, its a select, so set the value to "All" which is an option I have, otherwise the 7th element is a text input, so set the val to ""
In this case you can simplify your code without the need for arrays:
$('#clear-button').click(function () {
$('input.clearable-field').val('');
$('select.clearable-field').val('All');
});

HTML 5 toggling the contenteditable attribute with javascript

enter code hereI am trying to make something editable online with a function like this
function toggle_editable (div, cssclass) {
var classToEdit = document.getElementsByClassName(cssclass)
for (i = 0;classToEdit.length; i++) {
if (classToEdit[i].contentEditable == false) {
classToEdit[i].contentEditable = true ;
}
if (classToEdit[i].contentEditable == true) {
classToEdit[i].contentEditable = false ;
}
}
}
classToEdit is a collection of HTML elements with the same class name or whatever document.getElementsByClassName(cssclass) returns
when going through the debugger it jumps over the line
classToEdit[i].contentEditable == true
as well as over the line
classToEdit[i].contentEditable == true
and does not execute the code in the braces following the if statements
this works however - meaning it sets the contenteditable property without hesitation
classToEdit.contenteditable = true;
as well as this
classToEdit.contenteditable = false;
(well obviously)
also this seemed to have no effect
classToEdit.contenteditable = !classToEdit.contenteditable
ideas anyone?
ps why is the loop
You've created an infinite loop here:
for (i = 0;classToEdit.length; i++) {
Should be:
for (var i = 0; i < classToEdit.length; i++) {
But, if you say classToEdit.contenteditable = true "works", you've to define "not working/is working" since the snippet doesn't definitely do what you expect it to do, if classToEdit is a HTMLCollection.
It looks like you'd want to toggle contentEditable values, you can do it like this:
for (var i = 0; i < classToEdit.length; i++) {
if (classToEdit[i].contentEditable == false) {
classToEdit[i].contentEditable = true ;
} else { // Notice else here, no need for another check
classToEdit[i].contentEditable = false;
}
}
Or simply without ifs in the loop:
classToEdit[i].contentEditable = !classToEdit[i].contentEditable;
Your current code will switch the value back to it's original in a case the value was false.
HTMLElement.contentEditable returns a string and not a boolean.
Hence, what you want to identify the state of your editable field is:
// Incorrect
classToEdit[i].contentEditable == true
// Coorect
classToEdit[i].contentEditable === 'true'
What's even better if you want to know the state of your fields is to use HTMLElement.isContentEditable
which returns a boolean:
classToEdit[i].contentEditable = !element.isContentEditable
Another way to refactor the above:
function toggleContentEdit() {
var editableFields = document.getElementsByClassName('editable');
[].forEach.call(editableFields, function(field){
var isEditable = field.isContentEditable;
field.setAttribute('contenteditable', !isEditable);
});
};
JSFiddle: http://jsfiddle.net/6qz3aotv/

How do I change the name of multiple selected html values?

I have about 20 check boxes. When the user selects these and then uses an alternate submit button, I need to change the name of the name/value pair, for the selected inputs.
Why does this function only change the name of every other selected input?
function sub_d()
{
for (i = 0; i < document.checks.OGname.length; i++) //for all check boxes
{
if (document.checks.OGname[i].checked == true)
{
document.checks.OGname[i].name="newname"; //change name of input
}
}
document.checks.submit();
}
The output:
newname
'105'
OGname
'106'
newname
'107'
OGname
'108'
newname
'109'
OGname
'110'
By renaming the first element of the list you have reduced the length of the list by one and deleted the first element. Next time through the loop the previous second element is now the first, and the second is the old third.
I'm no javascript expert, but something along the lines of this might work.
function sub_d()
{
i=0;
while (document.checks.OGname.length > i)
{
if (document.checks.OGname[i].checked="true")
{
document.checks.OGname[i].name="newname";
}else{
i++;
}
}
document.checks.submit();
}
As I said, no warranty or guarantee.
Would be great if you provide a more detailed description of your scenario, but I wish that my answer be useful.
function sub_d()
{
for (i = 0; i < document.checks.OGname.length; i++) //for all check boxes
{
if (document.checks.OGname[i].type == 'CHECKBOX')
if (document.checks.OGname[i].checked)
{
document.checks.OGname[i].name="newname"; //change name of input
}
}
document.checks.submit();
}
I usually manage dom collections in this way: (I don't know if is the best way)
function sub_d()
{
var theInputs = document.checks.getElementsByTagName('input');
for (var i = 0; i < theInputs.length; i++)
{
if (theInputs[i].type == 'CHECKBOX')
if (theInputs[i].checked)
{
theInputs[i].name="newname";
}
}
document.checks.submit();
}
With your guys help I came up with this, seems to work well. Let me know if it can be improved for others to use...
function sub_d()
{
for (i = 0; i < document.checks.OGname.length; i++) //for all check boxes
{
if (document.checks.OGname[i].checked == true)
{
document.checks.OGname[i].name="newname"; //change name of input data so we know it is for other function
//By renaming the first element of the list, we have reduced the length of the list by one
//and deleted the first element. This is why we need to keep i at it's current position after a name change.
i=i-1;
}
}
//When there is only one check box left it's propert length becomes undefined.
//We will need this statement for the last undefined check box not covered in the for loop
//We can no longer index user[0]
document.checks.OGname.name="newname";
document.checks.submit();//submit these checked values to the .exe
}

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