How to print an id get with document.getElementById? - javascript

HTML:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<script type="text/javascript" src="fuctions.js"></script>
<title>Count JS</title>
</head>
<body>
<fieldset>
<input type="number" value="1" id="num" min="1" max="5"/>
<button onclick="getValue()">
Submit
</button>
</fieldset>
</body>
</html>
JS:
function getValue() {
var x = parseInt(document.getElementById("num"));
alert(x);
}
I just want to print this value that I get using document.getElementById, but when I print appears it:
Can someone help?

.value returns value from input, in your case, you try convert DOMNode to Integer that will return NaN
var x = parseInt(document.getElementById("num").value);
Example

Add .value after document.getElementById
function getValue() {
var x = parseInt(document.getElementById("num").value);
alert(x);
}

Related

How do I trigger a JavaScript function when a button is pressed in HTML code

I am trying to create a calculator that solves the Pythagoras theorem. I have created a function inside a tag in my code which takes two arguments (one for each leg length of the right-angled triangle) The function works if I just do a console.log with two numbers as arguments and the function executes properly if it is inside the script tag. But I just want to know how to take the two arguments in the text boxes and then when I press the button make the result appear on the screen.
<html>
<main>
<head>
<!--Textboxes to input lengths of legs-->
<input type = "text" required placeholder= "1st legnth">
<br> <br>
<input type = "text" required placeholder= "2nd legnth">
<br> <br>
<button type = "submit">Give me the answer.
</head>
</main>
</html>
<script>
function solveforHyp (a, b)
{
var c = a*a + b*b;
return Math.sqrt(c);
}
var final = (solveforHyp(3, 4));
console.log(final);
</script>
add a span after the button to contain the final result:
<span id="final-result"></span>
add an onclick event to your button, it might look like this:
<button type="button" onclick="onButtonSubmit()"></button>
you might also give some relevant ID's to the input like this:
<input type = "text" id="first-length" required placeholder= "1st legnth">
<input type = "text" id="second-length" required placeholder= "2nd legnth">
and finally, write the onButtonSubmit function to access the inputs and call the solveforHyp function :
function onButtonSubmit(){
const firstValue = document.getElementById('first-length').value;
const secondValue = document.getElementById('second-length').value;
document.getElementById('final-result').innerText = solveforHyp(firstValue,secondValue); // finally, put the returned value in the created span.
}
First of all your document structure is entirely wrong, a lot of tags are not closed script is after the HTML tag, and content is written inside head tag and head is inside main, NO doctype declaration is done, and most importantly if you wanna submit something you should have a form at least with preventing its default behavior. Learn HTML before JavaScript Brother, and also its a good practice to use input type Number when you already know the input will be always a Number.
and here is the code what you are trying to make
<!DOCTYPE html>
<html>
<head>
<title>Example</title>
</head>
<body>
<form id="formOne">
<input type="number" required placeholder="1st legnth" id="first">
<br> <br>
<input type="number" required placeholder="2nd legnth" id="second">
<br> <br>
<button type="submit">Give me the answer</button>
</form>
</body>
<script>
let form = document.querySelector("#formOne");
let inputOne = document.querySelector("#first");
let inputTwo = document.querySelector("#second");
form.addEventListener("submit", function(e){
e.preventDefault();
console.log(Math.sqrt(Math.pow(inputOne.value,2) + Math.pow(inputTwo.value,2)));
})
</script>
</html>
Js file function to be called
function tryMe(arg) {
document.write(arg);
}
HTML FILE
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src='object.js'> </script>
<title>abc</title><meta charset="utf-8"/>
</head>
<body>
<script>
tryMe('This is me vishal bhasin signing in');
</script>
</body>
</html>
You can try like this:
<!DOCTYPE html>
<html>
<head>
<title>Parcel Sandbox</title>
<meta charset="UTF-8" />
</head>
<body>
<form id="form">
<input type="text" id="first_length" name="first_length" />
<input type="text" id="second_length" name="second_length" />
<input type="submit" value="Submit" />
</form>
<script>
function logSubmit(event) {
event.preventDefault();
var first_length = document.getElementById("first_length").value;
var second_length = document.getElementById("second_length").value;
var final = solveforHyp(first_length, second_length);
console.log(final);
}
const form = document.getElementById("form");
form.addEventListener("submit", logSubmit);
function solveforHyp(a, b) {
var c = a * a + b * b;
return Math.sqrt(c);
}
</script>
</body>
</html>

var x=document.getElementById("mytext").value;Why i change the value to innerHTMl or innerText,it do not work?

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<input type="text" id="mytext">
<input type="button" onclick="myfuction()" value="click">
<script type="text/javascript">
//the problem is here,why the value is ok?but innerText don't
function myfuction() {
var a = document.getElementById("[mytext][1]").value;
alert(a);
}
</script>
</body>
</html>
I want to enter text in the input box, and I will be prompted by clicking the button.
getElementById works on the ID attribute of the element.
function myfuction() {
var a = document.getElementById("mytext").value;
alert(a);
}
<input type="text" id="mytext">
<input type="button" onclick="myfuction()" value="click">

Javascript not working onchange

I've got a simple html and JS script, but it doesn't fire the alert message onchange when I enter 2 in the input number field.
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="viewport" content="width=device-width">
<script type="text/javascript">
function myFunction() {
var x = document.getElementById("partysize");
if (x==2) window.alert ("You entered" + x);
}
</script>
</head>
<body bgcolor="#6BD3FF" text="#000000" link="#0000EE" vlink="#551A8B" alink="#FF0000">
<div align="center">
<br> Please enter the party size:
<input type="number" id = "partysize" name="partySize" onchange="myFunction()" >
<br />
<input type="SUBMIT" name="submitButton">
</form>
<br />
</div>
</body>
</html>
ugh, fixed by getting the value of the element:
function myFunction() {
var x = document.getElementById("partysize").value;
if (x==2) window.alert ("You entered" + x);
}
You need to get the value from the input box but in your snippet x is the only dom element. Pass the value to the change handler using this.value. Also parseInt will convert the number value in string to number
function myFunction(x) {
if (parseInt(x, 10) === 2) {
alert("You entered" + x);
}
}
<body bgcolor="#6BD3FF" text="#000000" link="#0000EE" vlink="#551A8B" alink="#FF0000">
<div align="center">
<br> Please enter the party size:
<input type="number" id="partysize" name="partySize" onchange="myFunction(this.value)">
<br/>
<input type="submit" name="submitButton">
<br />
</div>
</body>

Set dynamic javascript value to html text input with sum

Please read the form and javascript carefully. My goal is grab text input value 'a' and 'b' then total integer value will be dynamically set to text input id called- 'x'. How can i set dynamic javascript value to html text input? Also it should be real time updating so user can see the total value of a+b on x. x is actually displaying the value and will be submitting this value if 'submit' button pressed.
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<script src="http://code.jquery.com/jquery-1.11.1.js" type="text/javascript"></script>
</head>
<body>
<form method="post">
<input type="text" id="a" value="5">
<input type="text" id="b" value="2">
<input type="text" id="x" value="dynamic_value_from_javascript">
<input type="submit" name="submit" value="submit">
</form>
<script type='text/javascript'>
$('#a').keyup(updatetxt);
$('#a').keydown(updatetxt);
var a = $('#a');
var b = $('#b');
var x = a+b;
function updatetxt() {
$('#x').val($(x).val());
}
</script>
</body>
</html>
Check this fiddle I have made recently,It will update real time. let me know if any query occurs
$(function() {
$( "#a" ).keyup(function() {
var a = $('#a').val();
var b = $('#b').val();
var c = parseInt(a) + parseInt(b);
$('#c').val(c);
});
$( "#b" ).keyup(function() {
var a = $('#a').val();
var b = $('#b').val();
var c = parseInt(a) + parseInt(b);
$('#c').val(c);
});
});
<input type="text" id="a" value="1"/><br>
<input type="text" id="b" value="2"/><br>
<input type="text" id="c" value=""/><br><br>
My Jsfiddle link
There are a few problems with your code, I have fixed them below:
You need to get values of a and b during the keyup events.
You need subscribe to keyup events of both a and b inputs.
In order to add integer values, you can use parseInt
Call updatetxt for the first time without any events, so that it can set the total value based on default values in the inputs
$('#a').keyup(updatetxt);
$('#b').keyup(updatetxt);
function updatetxt() {
var a = $('#a').val();
var b = $('#b').val();
var x = parseInt(a) + parseInt(b);
$('#x').val(x);
}
updatetxt();
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<input type="text" id="a" value="5">
<input type="text" id="b" value="2">
<input type="text" id="x" value="">

Store textbox values in a div tag

I have a textbox having id=add, a div having id=get and a button named Add. Now I'm trying to enter values in textbox, save them in to an array and then save that array elements in the div tag (using javascript). But I'm unable to do so. Please help.
<html>
<head>
<title>Content</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="stylesheets/keyword.css" rel="stylesheet">
<SCRIPT language="javascript">
//
var data = new array();
data= document.getElementById('add').value;
function copy()
{
document.getElementById('get').innerHTML=data;
// document.getElementById('get').innerHTML= document.getElementById('add').value;
// return true;
}
</SCRIPT>
</head>
<body>
<input type="text" name="add" id="add"/>
<input type="button" name="but1" onclick="copy()" value="Add"/>
<div id="get" class="keyword"></div>
</body>
</html>
Update your code as,
<html>
<head>
<title>Content</title>
<script language="javascript">
function copy() {
var data = document.getElementById('add').value;
document.getElementById('get').innerHTML += data + "<br/>";
}
</script>
</head>
<body>
<input type="text" name="add" id="add" />
<input type="button" name="but1" onclick="copy()" value="Add" />
<div id="get" class="keyword">
</div>
</body>
</html>
PS:Array (not array) is not required here,
This is because data doesn't have any value, you are trying to read the value of the text box before setting a value and also it should be Array()
Try this instead
function copy()
{
var data = new Array();
data= document.getElementById('add').value;
document.getElementById('get').innerHTML=data;
}
JsBin
Three issues in your code:
array() is not recognized in javascript, it's Array().
You are trying to read the value of the text box before a value can be set to it here:
data= document.getElementById('add').value;
function copy(){
It should be:
function copy()
{
data[0]= document.getElementById('add').value;
data is an array. If you want to store a value, it should be used with an index.
JSFiddle
<html>
<head>
<title>Content</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link href="stylesheets/keyword.css" rel="stylesheet">
<SCRIPT language="javascript">
//
var data = new Array();
function copy()
{
data = document.getElementById('add').value;
document.getElementById('get').innerHTML = data; document.getElementById('get').innerHTML= document.getElementById('add').value;
// return true;
}
</SCRIPT>
</head>
<body>
<input type="text" id="add"/>
<input type="button" name="but1" onclick="copy()" value="Add"/>
<div id="get" class="keyword"></div>
</body>
</html>

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