documnet.getElementById does not fetch the value . what is going wrong? - javascript

i am sure this is quite a numb question to ask and most probably the most basic one. i am just a starter for JS.
i am trying to access the value of input field by document.getElementById and it is returning null to me i am not sure why here is the code.
<html>
<head>
<script type="text/javascript">
var name = document.getElementById("e_name");
alert(name);
</script>
</head>
<body>
<form action="" method="post">
<input type="text" name="name" id="e_name" value="Enter your Name"/>
<input type="submit" name="submit"/>
</form>
</body>
</html>
the following code prints the value null in alert box. what is wrong?
Update :
When i use the following code.
<html>
<head>
</head>
<body>
<form action="" method="post">
<input type="text" name="name" id="name" value="Enter your Name"/>
<input type="submit" name="submit"/>
</form>
<script type="text/javascript">
var name = document.getElementById('name').value;
alert(name);
</script>
</body>
</html>
it prints Enter your Name but if i change the value it does not print the changed value. i would want to perform the following for validation purpose
a) holds the value of e_name in a javascript variable in the head tag
b) so that i should be able to process it for validation.
how do i do it?

Because you're calling that line of script even before document object is ready!
Try this
<body>
<form action="" method="post">
<input type="text" name="name" id="e_name" value="Enter your Name"/>
<input type="submit" name="submit"/>
</form>
<script type="text/javascript">
var name = document.getElementById("e_name").value;
alert(name);
</script>
</body>
Or this in your head tag.
<script type="text/javascript">
window.onload = function() {
var name = document.getElementById("e_name");
alert(name);
}
</script>

The Javascript code is executing before that HTML has loaded. The element with id="e_name" doesn't actually exist in the document yet.

function validate()
{
var nam=name.value;
alert("name"+nam);
}

Related

need to add onsubmit Event Attribute to a form via javascript and thank you

so here is what trying to get i need only a way to add ( onsubmit="submitted=true") to the form via javascript
and thank you guys
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<script type="text/javascript">
var submitted=false;
</script>
<iframe name="invisibleFrame" id="invisibleFrame" style="display:none;" onload="if(submitted)
{window.location='Confirmation.html';}">
</iframe>
<form action="https://link.com" method="post" target="invisibleFrame" onsubmit="submitted=true;" id="contact_form" autocomplete="on">
<label for="entry.164" class="phone" >phone</label><br>
<input type="text" name="entry.1647992981" placeholder="phone" required><br>
<label for="entry.1">name</label><br>
<input type="text" name="entry.1" placeholder="name" required><br>
<label for="entry.7">city</label><br>
<input type="text" name="entry.7" placeholder="city" required><br><br>
<button type="submit" class="order-button">submit</button>
</form>
</body>
</html>
actually im not good at all in coding so i just trying to get something done . thank you guys
Use addEventListener() to add a listener that does what you want.
<script>
document.querySelector("form").addEventListener("submit", function() {
submitted = true;
});
</script>
If you just want to make the iframe load the confirmation page when you submit the form, you can do that in the listener instead of setting the variable.
<script>
document.querySelector("form").addEventListener("submit", function() {
let iframe = document.querySelector("#invisibleFrame");
iframe.src = "Confirmation.html";
iframe.style.display = 'block';
});
</script>

Why is my HTML form not displaying my input?

I'm pretty new to JavaScript and am creating a simple page to output the form values. But there's seem to be a problem that it is not showing.
<html>
<head>
<title>Return first and last name from a form - w3resource</title>
</head>
<body>
<form id="form1" onsubmit="form()">
First name: <input type="text" name="fname" value="David"><br>
Last name: <input type="text" name="lname" value="Beckham"><br>
<input type="submit" value="Submit">
</form>
<p id="firstname"></p>
<script>
function form() {
var x = document.getElementById("form1").elements[0].value;
document.getElementById("firstname").innerHTML = x;
}
</script>
</body>
</html>
I can't seem to find any problems, the console was fine with the code.
You have to stop the form from submitting.
<html>
<head>
<title>Return first and last name from a form - w3resource</title>
</head>
<body>
<form id="form1" onsubmit="return form()">
First name: <input type="text" name="fname" value="David"><br>
Last name: <input type="text" name="lname" value="Beckham"><br>
<input type="submit" value="Submit">
</form>
<p id="firstname"></p>
<script>
function form() {
var x = document.getElementById("form1").elements[0].value;
document.getElementById("firstname").innerHTML = x;
return false;
}
</script>
</body>
</html>
Use an event listener to handle the submit and preventDefault() for stopping the submission. Following code is tested and working.
<html>
<head>
<title>Return first and last name from a form - w3resource</title>
</head>
<body>
<form id="form1">
First name: <input type="text" name="fname" value="David"><br>
Last name: <input type="text" name="lname" value="Beckham"><br>
<input type="submit" value="Submit">
</form>
<p id="firstname"></p>
<script>
document.getElementById("form1").addEventListener("submit", form);
function form(e) {
e.preventDefault();
var x = document.getElementById("form1").elements[0].value;
document.getElementById("firstname").innerHTML = x;
}
</script>
</body>
</html>
<script src="script.js"></script>
</body>
</html>

Display Post value from HTML form to another HTML form

Quick question. I am starting learn on local storage HTML5. How can I get value from a form and display that value on another HTML form page?
For example, I have two forms here.
If I fill on form 1 and click submit button, and the value will display on form 2 in readable only.
I tried below:
HTML Form 1:
<html>
<head>
<title>Save Value</title>
<script type="text/javascript">
function saveVal() {
var inputFirst = document.getElementById("name").value;
localStorage.setItem("name", inputFirst);
inputFirst = localStorage.getItem("name");
}
</script>
</head>
<body>
<form action="display.html" method="get">
<label>
First Name:
<input name="name" size="20" maxlength="25" type="text" id="name" />
</label>
<input type="submit" value="submit" onclick="saveVal()"/>
</form>
</body>
</html>
HTML Form 2:
<html>
<head>
<title>Display</title>
<script type="text/javascript">
function result() {
var storedVal = document.getElementById("name");
storedVal.value = localStorage.getItem("name");
}
</script>
</head>
<body>
<form action="#">
<label>
First Name:
<input name="name" size="20" maxlength="25" type="text" id="name" readonly="readonly" />
</label>
</form>
</body>
</html>
In display.html you didn't call function result(),
try this,
<html>
<head>
<title>Display</title>
</head>
<body>
<form action="#">
<label>
First Name:
<input name="name" size="20" maxlength="25" type="text" id="name" readonly="readonly" />
</label>
<script type="text/javascript">
var storedVal = document.getElementById("name");
storedVal.value = localStorage.getItem("name");
</script>
</form>
</body>
</html>

Alert box shows form data when clicking button

I am looking to create a button at the bottom of a form that will create an alert box that will show the form data entered. Form includes:
First Name
Last Name
Address 1
Address 2
City
State
Zip
Phone
Fax
Once the form is completed, the button is clicked and an alert box pops up showing the form data entered.
Does anyone know how to accomplish without the form actually being submitted or validated? There is no database for the form data to be submitted to, so there is no database to pull the information from.
Any help would be greatly appreciated.
I have not included the form code due to its length, but the current code I am working with for the Alert Box looks like this:
<script>
function display_alert()
{
alert("");
}
</script>
<body>
<input type="button" onclick="display_alert()" value="Display alert box">
</body>
If I get it right you need something like this:
<html>
<head>
<script type="text/javascript">
window.onload = function(){
document.getElementById('send').onclick = function(e){
alert(document.getElementById("name").value);
return false;
}
}
</script>
</head>
<body>
<form method="post">
<input type="text" name="name" id="name" />
<input type="submit" name="send" id="send" value="send" />
</form>
</body>
</html>
I don't really get what you mean with a database to pull the information from, but the example uses a click event to get the data from the form field and shows it in an alert without a submit.
html code:
<html>
<SCRIPT SRC="PR8_4.JS"></SCRIPT>
<body>
<form name=details>
<table>
<tr><td>ENTER FRIST NAME:<input type=text name=fname></td></tr>
<tr><td>ENTER LAST NAME:<input type=text name=lname></td></tr>
<tr><td>ENTER PHONE NUM :<input type=text name=phnum></td></tr>
</table>
<input type="button" value="Click Me" onclick="display();">
</form>
</body>
</html>
javascript code:
function display()
{
var x=document.details.fname.value;
var y=document.details.lname.value;
var z=document.details.phnum.value;
alert("FIRST NAME:"+x+" "+"LAST NAME:"+y+" "+"PHONE NUMBER:"+z);
}
To stop a form submitting you can create an onsubmit event within the tag and return false - e.g. ...form elements.... This has the benefit of working when someone submits the form by pressing the enter key as well as pressing the submit button.
Thus, to achieve what you desire you could create a function (lets call it formAlert) and call it from the onsubmit event e.g. ...form elements...
The formAlert function would look something like:
function formAlert() {
alert_string = '';
alert_string = alert_string + document.getElementById('first_name').value;
alert_string = alert_string + ' ';
alert_string = alert_string + document.getElementById('last_name').value;
alert(alert_string);
}
and this would correspond to a form looking like:
<form id="foo" onsubmit="formAlert(); return false;">
<p><label for="first_name">First Name<label><input type="text" id="first_name" value="fred" /></p>
<p><label for="last_name">Last Name<label><input type="text" id="last_name" value="blogs" /></p>
<p><input type="submit" value="click me" /></p>
</form>
Note1, this won't be a pretty modal box - it'll simply display "fred blogs" in a Javascript alert box.
Note2, if there is a Javascript error your form will still submit (although in the example here it'll submit to itself).
Here is a JS Fiddle demonstrating the above code: http://jsfiddle.net/D59su/
I think this might be what you're looking for:
<!DOCTYPE html>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="javascriptform.css">
</head>
<body>
<form name= "details"><div class="box1"><div id="a"><input type="text" name="lastname" placeholder="LAST NAME"></div><br>
<div id="b"><input type="text" name="firstname" placeholder="FIRST NAME"></div><br>
<div id="c"><input type="e-mail" name="email" placeholder="E-MAIL"></div><br>
<div id="d"><input type="password" name="password" placeholder="PASSWORD"></div><br>
<div id="sub-button"><button onclick="getdetails();">submit</button></div></form>
</div>
<script>
function getdetails()
{
var a = document.forms["details"]["lastname"].value;
var b = document.forms["details"]["firstname"].value;
var c= document.forms["details"]["email"].value;
alert("Your name is "+a+" "+b+". Your e-mail is "+c);
}
</script>
</body>
</html>
It Is Very Simple
Using .value will help.
HTML:
<form onsubmit="return myFunction()>
<input type="text" id="name>
<input type="submit" value="SEND">
Use return before your function
Javascript:
function myFunction () {var name = document.getElementById("name").value; alert("Hi " + name)}
After Submitting It Will Show As (If I Write Alex and Submit It)
Hi Alex
Hope it will work

Show data in a single page Javascript and HTML forms

I'm new to Javascript. Can I show direct data from an HTML form on the same page. My code is here:
<html>
<head>
<title></title>
</head>
<script>
document.getElementById("btn").onclick = avc;
function avc(){
var a = document.getElementsByName("firstname").value;
document.getElementsByName("abc").innerHTML = a;
}
</script>
<body>
<form method="post">
First name: <input id="fname" type="text" name="firstname"><br>
<input id="btn" type="submit">
</form>
<div name="abc"></div>
</body>
</html>
Using the ID for the element would also work when getting the value.
var a = document.getElementById('fname').value;
Yes you can with
<script>
document.getElementById('abc').innerHTML=document.getElementById('fname').value;
</script>
at the end
if you want that every time you write something in text box changes the value in div abc try this:
<html>
<head></head>
<body>
<form method="post">
First name: <input id="fname" type="text" name="firstname" onKeyUp="f()"><br>
<input id="btn" type="submit">
</form>
<div id="abc"></div>
<script>
function f() {
document.getElementById('abc').innerHTML=document.getElementById('fname').value;
}
f(document.getElementById('fname').value);
</script>
</body>
</html>
Yes, but you need to subscript the correct element like so...
var a = document.getElementsByName("firstname")[0].value;

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