Develop Reference

How do I get the id of a element in a form?

I need to get the id of an element within a form so I can tag the element as "false" or "true". Or, alternately, I need a way to associate a name with an element that can I pull in javascipt so I can change the associated value.
var form = document.getElementById("myForm");
form.elements[i].value
Those lines of code is what I tried but it doesn't seem to work.
Edit:
function initial(){
if (localStorage.getItem("run") === null) {
var form = document.getElementById("myForm").elements;
for(var i = 0; i < 1 ; i++){
var id = form.elements[i].id;
sessionStorage.setItem(id,"false");
}
localStorage.setItem("run", true);
}
}
So basically when I run the page, I want a localStorage item attached to all the buttons on the screen. I want this to run once so I can set all the items to false. Problem is I don't know how to get the ids so I have a value to attach to the button. Any idea of how to accomplish a task like this.
Edit2:
function initial(){
if (localStorage.getItem("run") === null) {
var form = document.getElementById("myForm");
var tot = document.getElementById("myForm").length;
for(var i = 0; i < tot ; i++){
sessionStorage.setItem(form.elements[i].id,"false");
}
localStorage.setItem("run", true);
}
}
This is the new code. It mostly seems to work but for some reason only the first value is getting set to false. Or maybe it has to do with this function, I'm not sure.
function loader(){
var form = document.getElementById("myForm");
var tot = 5;
for(var i = 0; i < 5 ; i++){
if(sessionStorage.getItem(form.elements[i].id) === "true"){
document.getElementById(form.elements[i].id).style.backgroundColor = "green";
return ;
}else{
document.getElementById(form.elements[i].id).style.backgroundColor = "red";
return false;
}
}
}
Anyways, I'm running both of these at the same time when the page is executed so they are all set to false and turn red. But when a button is properly completed, the color of the button turns green.

It's available via the id property on the element:
var id = form.elements[i].id;
More on MDN and in the spec.
Live Example:
var form = document.getElementById("myForm");
console.log("The id is: " + form.elements[0].id);
<form id="myForm">
<input type="text" id="theText">
</form>

You're already storing all the elements in the form so it must be :
var form = document.getElementById("myForm").elements;
var id = form[i].id;
Or remove the elements part from the form variable like :
var form = document.getElementById("myForm");
var id = form.elements[i].id;

Display JavaScript Array Elements inside Div

There's a textarea in the webpage to enable user to add address. User may enter 'n' number of addresses by clicking on the Add Address button. When user clicks on the Display Address button, all the addresses entered should be displayed inside the "result" div tag as per following format:
Address 1
Address entered by user
Address 2
Address entered by user
.....
Here's the HTML code
<div id="body" align="left">
<h2>Address Details</h2>
Enter the Address : <textarea id="address"></textarea><br>
<button id="add" onclick="addAddress();">Add Address</button>
<button id="display" onclick="displayAddress();">Display Address</button>
</div>
<div id="result" align="right"></div>
Here's the JS function to accept the address and store it in an array:
var address = [];
function addAddress(){
var addr = document.getElementById("address");
if(addr.value.replace(/^\s+|\s+$/gm,'') !=="") {
address.push(addr.value);
addr.value = "";
}
}
And here's the function to display the address inside the result div in the specified format (which does not work)
function displayAddress(){
var display = [];
var addrno = [];
var result = document.getElementById("result");
for(var i=0; i<address.length; i++){
display[i] = address[i];
addrno[i] = "Address "+(i+1);
}
result.innerHTML = addrno[i]+"<br>"+display[i]+"<br>";
}
Any help would be greatly appreciated.

Hm, if I understand your question correctly, you could try doing something like this:
function displayAddress(){
var display = [];
var addrno = [];
var result = document.getElementById("result");
for(var i=0; i<address.length; i++){
display[i] = address[i];
addrno[i] = "Address "+(i+1);
result.innerHTML += addrno[i]+"<br>"+display[i]+"<br>";
}
}
All I changed was move result.innerHTML += addrno[i]+"<br>"+display[i]+"<br>"; inside your for loop so it can access the variable i uppon each itteration and changed it so it added the string addrno[i]+"<br>"+display[i]+"<br>"; to the DOM by using += on result.innerHTML rather than = (so it doesn't override it, rather it appends to it)

How to get element by name with $key

PHP
//Here is my html for qty
<p>Qty : <input type="number" value="" name="qty<?php echo $key ?> onChange="findTotal()"/>
JS function
function findTotal() {
var arr = document.getElementsByName('qty');
...
document.getElementById('result').value = decimalPlaces(tot, 2);
}
My qty name needs key for post array. How do I get name inside js function to calculate quantities?

You can use
document.querySelector("input['name^='qty']").value
if you don't have jQuery.
This will select an input with name attribute starting with "qty". If you have multiple inputs which match the criteria you can select them all using
document.querySelectorAll("input[name^='qty']")
which will return a NodeList. You can read more about this here.

You can do something like this
var myVar = document.getElementsByTagName("somename");
//do something else
If you are using jquery
value = $( "input[name^='qtd']" ).val();
//it will pick the input wich name starts with 'qtd'

In pure DOM, you could use getElementsByTagName to grab all input elements, and loop through the resulting array. Elements with name starting with 'qty' get pushed to another array:
var eles = [];
var inputs = document.getElementsByTagName("input");
for(var i = 0; i < inputs.length; i++) {
if(inputs[i].name.indexOf('qty') == 0) {
eles.push(inputs[i]);
}
}

Don't query the element by the name attribute's value. I'm not sure what's the purpose of the key and why you need it in the findTotal method, but here's an example:
<p>Qty : <input type="number" value="" name="qtyMyKey" onChange="findTotal(event)" /></p>
<script>
function findTotal(e) {
var inputEl = e.target,
inputName = inputEl.getAttribute('name'),
myKey;
if (typeof inputName === 'string') {
myKey = inputName.replace('qty', '');
}
console.log(myKey);
//var arr = document.getElementsByName('qty');
//document.getElementById('result').value = decimalPlaces(inputEl.value(), 2);
}
</script>
Here's the jsFiddle demo.

Input entry is not catched in Javascript

I tried to build an application in which , there is one HTML page from which I get single input entry by using Submit button, and stores in the container(data structure) and dynamically show that list i.e., list of strings, on the same page
means whenever I click submit button, that entry will automatically
append on the existing list on the same page.
But in this task, firstly I try to catch that input in javascript file, and I am failing in the same. Can you tell me for this, which command will I use ?
Till now my work is :-
HTML FILE :-
<html>
<head>
<script type = "text/javascript" src = "operation_q_2.js"></script>
</head>
<body>
Enter String : <input type= "text" name = "name" id = "name_id"/>
<button type="button" onClick = "addString(this.input)">Submit</button>
</body>
</html>
JAVASCRIPT FILE:-
function addString(x) {
var val = x.name.value;
//var s = document.getElementById("name_id").getElementValue;//x.name.value;
alert(val);
}
EDITED
My New JAVASCRIPT FILE IS :-
var input = [];
function addString(x) {
var s = document.getElementById("name_id").value;//x.name.value;
input.push(input);
var size = input.length;
//alert(size);
printArray(size);
}
function printArray(size){
var div = document.createElement('div');
for (var i = 0 ; i < size; ++i) {
div.innerHTML += input[i] + "<br />";
}
document.body.appendChild(div);
//alert(size);
}
Here it stores the strings in the string, but unable to show on the web page.

See this fiddle: http://jsfiddle.net/MjyRt/
Javascript was almost right
function addString(x) {
var s = document.getElementById("name_id").value;//x.name.value;
alert(s);
}

Try to use jQuery (simpler)
function addString() {
var s = $('#name_id').val();//value of input;
$('#list').append(s+"<br/>");//list with entries
}
<div id='list'>
</div>

storing user input in array

I need to do the following (I'm a beginner in programming so please excuse me for my ignorance): I have to ask the user for three different pieces of information on three different text boxes on a form. Then the user has a button called "enter"and when he clicks on it the texts he entered on the three fields should be stored on three different arrays, at this stage I also want to see the user's input to check data is actually being stored in the array. I have beem trying unsuccessfully to get the application to store or show the data on just one of the arrays. I have 2 files: film.html and functions.js. Here's the code. Any help will be greatly appreciated!
<html>
<head>
<title>Film info</title>
<script src="jQuery.js" type="text/javascript"></script>
<script src="functions.js" type="text/javascript"></script>
</head>
<body>
<div id="form">
<h1><b>Please enter data</b></h1>
<hr size="3"/>
<br>
<label for="title">Title</label> <input id="title" type="text" >
<br>
<label for="name">Actor</label><input id="name" type="text">
<br>
<label for="tickets">tickets</label><input id="tickets" type="text">
<br>
<br>
<input type="button" value="Save" onclick="insert(this.form.title.value)">
<input type="button" value="Show data" onclick="show()"> <br>
<h2><b>Data:</b></h2>
<hr>
</div>
<div id= "display">
</div>
</body>
</html>
var title=new Array();
var name=new Array();
var tickets=new Array();
function insert(val){
title[title.length]=val;
}
function show() {
var string="<b>All Elements of the Array :</b><br>";
for(i = 0; i < title.length; i++) {
string =string+title[i]+"<br>";
}
if(title.length > 0)
document.getElementById('myDiv').innerHTML = string;
}

You're not actually going out after the values. You would need to gather them like this:
var title = document.getElementById("title").value;
var name = document.getElementById("name").value;
var tickets = document.getElementById("tickets").value;
You could put all of these in one array:
var myArray = [ title, name, tickets ];
Or many arrays:
var titleArr = [ title ];
var nameArr = [ name ];
var ticketsArr = [ tickets ];
Or, if the arrays already exist, you can use their .push() method to push new values onto it:
var titleArr = [];
function addTitle ( title ) {
titleArr.push( title );
console.log( "Titles: " + titleArr.join(", ") );
}
Your save button doesn't work because you refer to this.form, however you don't have a form on the page. In order for this to work you would need to have <form> tags wrapping your fields:
I've made several corrections, and placed the changes on jsbin: http://jsbin.com/ufanep/2/edit
The new form follows:
<form>
<h1>Please enter data</h1>
<input id="title" type="text" />
<input id="name" type="text" />
<input id="tickets" type="text" />
<input type="button" value="Save" onclick="insert()" />
<input type="button" value="Show data" onclick="show()" />
</form>
<div id="display"></div>
There is still some room for improvement, such as removing the onclick attributes (those bindings should be done via JavaScript, but that's beyond the scope of this question).
I've also made some changes to your JavaScript. I start by creating three empty arrays:
var titles = [];
var names = [];
var tickets = [];
Now that we have these, we'll need references to our input fields.
var titleInput = document.getElementById("title");
var nameInput = document.getElementById("name");
var ticketInput = document.getElementById("tickets");
I'm also getting a reference to our message display box.
var messageBox = document.getElementById("display");
The insert() function uses the references to each input field to get their value. It then uses the push() method on the respective arrays to put the current value into the array.
Once it's done, it cals the clearAndShow() function which is responsible for clearing these fields (making them ready for the next round of input), and showing the combined results of the three arrays.
function insert ( ) {
titles.push( titleInput.value );
names.push( nameInput.value );
tickets.push( ticketInput.value );
clearAndShow();
}
This function, as previously stated, starts by setting the .value property of each input to an empty string. It then clears out the .innerHTML of our message box. Lastly, it calls the join() method on all of our arrays to convert their values into a comma-separated list of values. This resulting string is then passed into the message box.
function clearAndShow () {
titleInput.value = "";
nameInput.value = "";
ticketInput.value = "";
messageBox.innerHTML = "";
messageBox.innerHTML += "Titles: " + titles.join(", ") + "<br/>";
messageBox.innerHTML += "Names: " + names.join(", ") + "<br/>";
messageBox.innerHTML += "Tickets: " + tickets.join(", ");
}
The final result can be used online at http://jsbin.com/ufanep/2/edit

You have at least these 3 issues:
you are not getting the element's value properly
The div that you are trying to use to display whether the values have been saved or not has id display yet in your javascript you attempt to get element myDiv which is not even defined in your markup.
Never name variables with reserved keywords in javascript. using "string" as a variable name is NOT a good thing to do on most of the languages I can think of. I renamed your string variable to "content" instead. See below.
You can save all three values at once by doing:
var title=new Array();
var names=new Array();//renamed to names -added an S-
//to avoid conflicts with the input named "name"
var tickets=new Array();
function insert(){
var titleValue = document.getElementById('title').value;
var actorValue = document.getElementById('name').value;
var ticketsValue = document.getElementById('tickets').value;
title[title.length]=titleValue;
names[names.length]=actorValue;
tickets[tickets.length]=ticketsValue;
}
And then change the show function to:
function show() {
var content="<b>All Elements of the Arrays :</b><br>";
for(var i = 0; i < title.length; i++) {
content +=title[i]+"<br>";
}
for(var i = 0; i < names.length; i++) {
content +=names[i]+"<br>";
}
for(var i = 0; i < tickets.length; i++) {
content +=tickets[i]+"<br>";
}
document.getElementById('display').innerHTML = content; //note that I changed
//to 'display' because that's
//what you have in your markup
}
Here's a jsfiddle for you to play around.