Develop Reference

JavaScript: click event for same class name

I've the following code snippet. The issue is onclick event doesn't fire for the second label, which has the same class as the first one. Why is that?
I searched online and found multiple solutions but all of them are in jQuery. But I want it in pure JavaScript. Does anyone know what am I doing wrong here?
var label = document.getElementsByClassName('text');
label[0].onclick = function() {
console.log(true);
};
<label class="text">Hello</label>
<label class="text">World!</label>
PS: I know this question has been asked here multiple times (but the solutions are for jQuery). So please don't mark this question as duplicate :/

You could use event delegation :
document.body.onclick = function (ev) {
if (ev.target.getAttribute("class") == "text") {
console.log(true);
}
};
<label class="text">Hello</label>
<label class="text">World!</label>
Thanks to event delegation new labels are also clickable :
var nLabels = 2;
document.body.onclick = function (ev) {
var newLabel;
if (ev.target.getAttribute("class") == "text") {
console.log(ev.target.textContent);
} else if (ev.target.id == "btn-add-label") {
newLabel = document.createElement("label");
newLabel.setAttribute("class", "text");
newLabel.textContent = " new label #" + (nLabels++);
document.body.appendChild(newLabel);
}
};
<button type="button" id="btn-add-label">Add label</button>
<label class="text">Hello</label>
<label class="text">World!</label>

label is an array of all the elements with class text, so label[0] will only apply to the first element in the document. Simplest way to do it would probably be with a loop such as
for (var i = 0; i<label.length; i++){
label[i].onclick = function() {
console.log(true);
};

var label = document.getElementsByClassName('text');
for (var i = 0; i<label.length; i++) {
label[i].oncllick = function () { console.log(true); };
}

try this
var label = document.getElementsByClassName('text');
for (var i = 0; i < label.length; i++) {
label[i].onclick = function() {
console.log(true);
};
}

Accessing Stored Object

I have an object "Driver" defined at the beginning of my script as such:
function Driver(draw, name) {
this.draw = draw;
this.name = name;
}
I'm using this bit of JQuery to create new drivers:
var main = function () {
// add driver to table
$('#button').click(function ( ) {
var name = $('input[name=name]').val();
var draw = $('input[name=draw]').val();
var draw2 = "#"+draw;
var name2 = "driver"+draw
console.log(draw2);
console.log(name2);
if($(name2).text().length > 0){
alert("That number has already been selected");}
else{$(name2).text(name);
var name2 = new Driver(draw, name);}
});
That part is working great. However, when I try later on to access those drivers, the console returns that it is undefined:
$('.print').click(function ( ) {
for(var i=1; i<60; i++){
var driverList = "driver"+i;
if($(driverList.draw>0)){
console.log(driverList);
console.log(driverList.name);
}
If you're interested, I've uploaded the entire project I'm working on to this site:
http://precisioncomputerservices.com/slideways/index.html
Basically, the bottom bit of code is just to try to see if I'm accessing the drivers in the correct manner (which, I'm obviously not). Once I know how to access them, I'm going to save them to a file to be used on a different page.
Also a problem is the If Statement in the last bit of code. I'm trying to get it to print only drivers that have actually been inputed into the form. I have a space for 60 drivers, but not all of them will be used, and the ones that are used won't be consecutive.
Thanks for helping out the new guy.

You can't use a variable to refer to a variable as you have done.
In your case one option is to use an key/value based object like
var drivers = {};
var main = function () {
// add driver to table
$('#button').click(function () {
var name = $('input[name=name]').val();
var draw = $('input[name=draw]').val();
var draw2 = "#" + draw;
var name2 = "driver" + draw
console.log(draw2);
console.log(name2);
if ($(name2).text().length > 0) {
alert("That number has already been selected");
} else {
$(name2).text(name);
drivers[name2] = new Driver(draw, name);
}
});
$('.print').click(function () {
for (var i = 1; i < 60; i++) {
var name2 = "driver" + i;
var driver = drivers[name2];
if (driver.draw > 0) {
console.log(driver);
console.log(driver.name);
}

What is the plain Javascript equivalent of .each and $(this) when used together like in this example?

What is the plain Javascript equivalent of .each and $(this).find when used together in this example?
$(document).ready(function(){
$('.rows').each(function(){
var textfield = $(this).find(".textfield");
var colorbox = $(this).find(".box");
function colorchange() {
if (textfield.val() <100 || textfield.val() == null) {
colorbox.css("background-color","red");
colorbox.html("Too Low");
}
else if (textfield.val() >300) {
colorbox.css("background-color","red");
colorbox.html("Too High");
}
else {
colorbox.css("background-color","green");
colorbox.html("Just Right");
}
}
textfield.keyup(colorchange);
}
)});
Here's a fiddle with basically what I'm trying to accomplish, I know I need to use a loop I'm just not sure exactly how to set it up. I don't want to use jquery just for this simple functionality if I don't have to
http://jsfiddle.net/8u5dj/
I deleted the code I already tried because it changed every instance of the colorbox so I'm not sure what I did wrong.

This is how to do what you want in plain javascript:
http://jsfiddle.net/johnboker/6A5WS/4/
var rows = document.getElementsByClassName('rows');
for(var i = 0; i < rows.length; i++)
{
var textfield = rows[i].getElementsByClassName('textfield')[0];
var colorbox = rows[i].getElementsByClassName('box')[0];
var colorchange = function(tf, cb)
{
return function()
{
if (tf.value < 100 || tf.value == null)
{
cb.style.backgroundColor = 'red';
cb.innerText = "Too Low";
}
else if (tf.value > 300)
{
cb.style.backgroundColor = 'red';
cb.innerText = "Too High";
}
else
{
cb.style.backgroundColor = 'green';
cb.innerText = "Just Right";
}
};
}(textfield, colorbox);
textfield.onkeyup = colorchange;
}

var rows = document.querySelectorAll('.rows');
for (var i=0; i<rows.length; i++) {
var row = rows[i];
var textfield = row.querySelector('.textfield');
var colorbox = row.querySelector('.box');
// ...
}
Note that you must use a for loop to iterate the rows because querySelectorAll() does not return an array, despite appearances. In particular, that means that .forEach() isn't valid on the returned list.

assign parameter value of an object javascript

I have been looking at this code for a long time trying to figure this out, but I am having no luck. This issue is that I want to assign a value to the parameter boxId. When I click on a box in the webpage an alert will come up displaying that id. I have tried many things, but nothing seems to work. I'm a beginner, so I feel at this point there just must be something that I don't know how to do.
constructor function:
function Box (boxId, name, color, number, coordinates) {
this.boxId = boxId;
this.name = name;
this.color = color;
this.number = number;
this.coordinates = coordinates;
}
global variables:
var boxes = [];
var counter = 0;
var boxId = 0;
init function:
window.onload = init;
function init() {
var generateButton = document.getElementById("generateButton");
generateButton.onclick = getBoxValues;
var clearButton = document.getElementById("clearButton");
clearButton.onclick = clear;
}
function to get values and create new boxes:
function getBoxValues() {
var nameInput = document.getElementById("name");
var name = nameInput.value;
var numbersArray = dataForm.elements.amount;
for (var i = 0; i < numbersArray.length; i++) {
if (numbersArray[i].checked) {
number = numbersArray[i].value;
}
}
var colorSelect = document.getElementById("color");
var colorOption = colorSelect.options[colorSelect.selectedIndex];
var color = colorOption.value;
if (name == null || name == "") {
alert("Please enter a name for your box");
return;
}
else {
var newbox = new Box(boxId, name, color, number, "coordinates");
boxes.push(newbox);
counter++;
var boxId = counter;
}
addBox(newbox);
var data = document.getElementById("dataForm");
data.reset();
}
function that adds boxes to the page:
function addBox(newbox) {
for (var i = 0; i < newbox.number; i++) {
var scene = document.getElementById("scene");
var div = document.createElement("div");
div.className += " " + "box";
div.innerHTML += newbox.name;
div.style.backgroundColor = newbox.color;
var x = Math.floor(Math.random() * (scene.offsetWidth-101));
var y = Math.floor(Math.random() * (scene.offsetHeight-101));
div.style.left = x + "px";
div.style.top = y + "px";
scene.appendChild(div);
div.onclick = display;
}
}
function to display alert when box is clicked:
function display(e) {
var a = e.target;
alert(a.counter);
}
function to clear boxes:
function clear() {
var elems = document.getElementsByClassName("box");
for ( k = elems.length - 1; k >= 0; k--) {
var parent = elems[k].parentNode;
parent.removeChild(elems[k]);
}
}
All of the other functions work just fine. I keep running into the id showing up as "undefined" when I click it, or the counter displaying "0" in the console log, for everything I've tried.

You can do it like this.
First, in addBox() embed boxId as an tag's attribute like this:
div.setAttribute('data-boxId', newbox.boxId);
Then in display() you can retrieve it back:
alert(e.target.getAttribute('data-boxId'));
Please tell if you do not prefer this approach and I will post an alternative (closure things).
Edit: Add jsfiddle example http://jsfiddle.net/runtarm/8FJpU/

One more try. Perhaps if you change:
var boxId = counter;
to
boxId = counter;
It will then use the boxId from the outer scope instead of the one defined in the function getBoxValues()

how to use an event object to dispaly information about a DOM element

I want to be able to click on a box (the boxes are created through code, and receive values from a form) in the webpage and display information about the box. I am working on a display() function that uses an event object and an alert to display information about the box. So far, I've had multiple odd failures in my attempt to do this, which leads me to believe that I'm not accessing object attributes correctly. I'm a beginner, so this could be really obvious, but thanks for the help.
constructor function:
function Box (counter, name, color, number, coordinates) {
this.counter = counter;
this.name = name;
this.color = color;
this.number = number;
this.coordinates = coordinates;
}
Global variables:
var boxes = [];
var counter = 0;
Init function:
function init() {
var generateButton = document.getElementById("generateButton");
generateButton.onclick = getBoxValues;
var clearButton = document.getElementById("clearButton");
clearButton.onclick = clear;
}
Function that gets values from the form:
function getBoxValues() {
var nameInput = document.getElementById("name");
var name = nameInput.value;
var numbersArray = dataForm.elements.amount;
for (var i = 0; i < numbersArray.length; i++) {
if (numbersArray[i].checked) {
number = numbersArray[i].value;
}
}
var colorSelect = document.getElementById("color");
var colorOption = colorSelect.options[colorSelect.selectedIndex];
var color = colorOption.value;
if (name == null || name == "") {
alert("Please enter a name for your box");
return;
} else {
var newbox = new Box(counter, name, color, number, "coordinates");
boxes.push(newbox);
counter++;
/*for(m = 0; m < boxes.length; m++) {
counter.newbox = boxes[m];
}*/
}
addBox(newbox);
var data = document.getElementById("dataForm");
data.reset();
}
function that assigns attributes to the boxes:
function addBox(newbox) {
for (var i = 0; i < newbox.number; i++) {
var scene = document.getElementById("scene");
var div = document.createElement("div");
div.className += " " + "box";
div.innerHTML += newbox.name;
div.style.backgroundColor = newbox.color;
var x = Math.floor(Math.random() * (scene.offsetWidth-101));
var y = Math.floor(Math.random() * (scene.offsetHeight-101));
div.style.left = x + "px";
div.style.top = y + "px";
scene.appendChild(div);
div.onclick = display;
//console.log(newbox);
//shows all of the property values of newbox in the console
//console.log(div); shows that it is an object in the console
//console.log(div.hasAttribute(number)); says false
}
}
display function:
function display(e) {
// alert(e.target); says its an html object
//alert(e.target.className); works - says "box"
//alert(e.target.hasAttribute(name)); says false
}
I've included some of the things i've found in comments.

The event object only gives you the name not a reference to the element. So... a couple of things.
First if you want to be browser agnostic you want something like (e.srcElement is for IE):
var x = e.target||e.srcElement;
Then get a reference to the element and do what you want:
var refToElement = document.getElementById(x.id);