Develop Reference

How to use concatenation with a variable used in a JavaScript JQuery function

I'm trying to use a variable that contains the name of a HTML element in a JQuery function for a radio button.
Normally I would do something like this:
var oldRadioValue = $('input[name="correct10")"]:checked').val();
But due to the radio button being created dynamically I need to do something like this:
var radioName = "correct"+questionCount;
var oldRadioValue = $('input[name=radioName]:checked').val();
When I check the console.log() I am getting undefined...
Thanks in advance for any help!

You should be able to it like this do this
var oldRadioValue = $('input[name="' + radioName + '"]:checked').val();

You can either use concatenation like this:
var oldRadioValue = $('input[name="'+radioName+'"]:checked').val()
Or the newer template literal syntax:
var oldRadioValue = $(`input[name="${radioName}"]:checked`).val();

Your need string concatenation to make this work.
var oldRadioValue = $('input[name=' + radioName + ']:checked').val();

Replace different Values in String?

I have a string which looks like this: (id:561644cdb40fbe0100247dd7:q) (id:56165d8a79c8c40100adbdb6:q) and I need to replace the different id's with different values. I already have the id's in a variable and trying to loop through with something like this var mailId = "(id:" + rplcId + ":q)"; But If I use the replace() function it doesnt work...Any other suggestions?

You can select the id with:
"(id:56165d8a79c8c40100adbdb6:q)".split(":")[1]

var id = "(id:561644cdb40fbe0100247dd7:q)";
var idArr = id.split(":");
idArr[1] = newId; //56165d8a79c8c40100adbdb6
var mailId = idArr[0]+idArr[1]+idArr[2];
and please provide your full code

JavaScript ID tag selection

Is there a better way to write jQuery('#'+ myId) in JavaScript.
I have an ID in a variable without the # character and jQuery('#'+ myId) looks ugly.
var myId = 'last-element-id';
jQuery('#'+ myId)
I'd like to avoid the + character to join the strings.
Thanks

But, have in mind that returned element is not a jQuery collection
function getElement(element) {
return document.getElementById(element)
}

function jQueryID(myId){
return jQuery('#'+ myId);
}
and then call like
jQueryId(myId);

As simple as that:
var myId = '#last-element-id';
jQuery(myId);
or
var myId = '#' + 'last-element-id'; // if 'last-element-id' is dynamically generated value
jQuery(myId);

I think when you are using jQuery, is better you stick with jQuery in all your code.
My offer is, create a function as below:
var getId = function(id){
return '#'+ id;
}
and call that anywhere you need, and stick with jQuery. like this:
$(getId(id));

jQuery selecting attribute value of multiple elements with name attribute

I have a form that has multiple input, select, textarea elements. With jQuery, How can I get the name attribute values of each element? I have tried the following but its not working:
var names = $('[name]');
names.each(function(){
console.log(names.attr('name'));
})

You need to use this within the each() to refer to the element within the current iteration. Your current code is attempting to get the name of a set of elements which is logically incorrect. Try this:
var names = $('[name]');
names.each(function(){
console.log($(this).attr('name'));
})

You are still using names within your each function. Try this:
var names = $('[name]');
names.each(function(index, name){
console.log($(name).attr('name'));
})

This should loop around all the required elements and output the name and value to the console.
$('input,select,textarea').each(function() {
var thisname = $(this).attr('name');
var thisval = $(this).val();
console.log('name = ' + thisname);
console.log('value = ' + thisval);
});

You can try this way too.
var $name = $("[name]");
$name.get().map(function(elem,index){
console.log($(elem).attr("name"));
});

Add a class to all the elements you wish to get the names of.
Then you get all the elements from that class and iterate them to get their names.
formElements = $('.form-element');
for(key in formElements) {
name = formElements[key].attr('name');
// do what you wish with the element's name
}
P.S. You may need to wrap formElements[key] in $(), have not tested it.

// Selects elements that have the 'name' attribute, with any value.
var htmlElements = $("[name]");
$.each(htmlElements, function(index, htmlElement){
// this function is called for each html element wich has attribute 'name'
var $element = $(htmlElement);
// Get name attribute for input, select, textarea only
if ($element.is("input") ||
$element.is("select") ||
$element.is("textarea")) {
console.log($element.attr("name"));
}
});

Give your input ID then call attr() method
$("#id").attr("name");

Get content of tag value using Javascript

i want know how i can retrieve the content of an HTML inner tag value for a specific ID, for example:
<span id="mycount" value="100">1</span>
i want retrieve the 100 value, i have tried this:
var num = document.getElementById('mycount').value;
i have also tried this:
var anchors = document.getElementById('mycount');
var num = anchors.value();
but doesn't work, how i can do it?

using jquery:
var num = $("#mycount").attr("value");
jQuery.attr()

Tag span can't have value property, it's not valid. Yes, it works, but it's a bad practice. Instead, you can use valid HTML5 attribute data-*.
In your case, that will be:
<span id="mycount" data-value="100">1</span>
and jQuery code to get this data value with .data() function is:
$(document).ready(function(){
var myvalue = $('#mycount').data('value');
alert(myvalue);
});
DEMO: http://jsfiddle.net/KhmGL/

var num = document.getElementById('mycount').getAttribute('value');
Take a look # MDN element.getAttribute.

to get attribute values we have to use getAttribute().
to get the value of mycount
var mycount = document.getElementById("mycount");
var num = mycount.getAttribute("value");
alert(num);