I looked and didn't find the case I have here -- a lot of the prior answers said 'wait for the 'onload' to call getElementById' but that's what I started with and it doesn't work -- getElementById returns null in this code in my index.php file:
<html>
<script type="text/javascript">
function checkPwd()
{
var thePwd = document.getElementById("theUsersPassword");
alert("the var thePwd is: " + thePwd);
}
</script>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Beta:</title>
</head>
<body onload="checkPwd()">
<form method="post" action="index.php">
Beta: <input name="theUsersPassword" type="password"><br/>
<input type="submit" value="Submit" />
</form>
</body>
</html>
getElementById get an element by ID not by name. You must change
<input name="theUsersPassword" type="password">
to
<input name="theUsersPassword" id="theUsersPassword" type="password" />
You are mixing up name and id
Edit:
In other words, you need to change
<input name="theUsersPassword" type="password">
to
<input name="theUsersPassword" id="theUsersPassword" type="password">
You can use the code below. getElementById returned an object not a value.
JavaScript
function checkPwd()
{
var thePwd = document.getElementById("theUsersPassword").value;
alert("the var thePwd is: " + thePwd);
}
Html
<input name="theUsersPassword" id="theUsersPassword" type="password">
Related
Here is My code:
HTML Portion
<form id="myform" action="whatever.php">
<lable name="text">enter text</label>
<input id="in" type="text" />
<input id="in2" type="text" />
<input type="submit" id="submit" />
</form>
jquery Code:
(function($){
$('#myform').on('click', '#submit', function(e) {
var val = $(this).find('#in').val();
$('ol.list').append('<li class="text-dark"><p>' + val + '.</p></li>');
e.preventDefault();
});
})(jQuery);
Output:
1.undefined.
2.undefined.
3.undefined.
On your code this inside the callback function points to the button with id #submit not the form itself.
You could just use the submit event, and your code will work fine
(function($){
$('#myform').on('submit', function(e) {
e.preventDefault();
var val = $(this).find('#in').val();
$('ol.list').append('<li class="text-dark"><p>' + val + '.</p></li>');
});
})(jQuery);
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
</head>
<body>
<ol class="list"></ol>
<form id="myform" action="whatever.php">
<label name="text">enter text</label>
<input id="in" type="text" />
<input id="in2" type="text" />
<input type="submit" id="submit" />
</form>
<script src="https://code.jquery.com/jquery-3.1.0.js"></script>
</body>
</html>
Then element with id in is child element of form element not the submit button.
You need to do the following by getting to parent form element and then find inside that your element as your input element is not in the submit button :
var val = $(this).closest("form").find('#in').val();
$(this).closest("form") will select the form and then find('#in') will select the element with id in and then val() will get the value of it.
See the working DEMO fiddle
I am absolutely new to javascript. I am trying to create my first html page and add some javascript on my html tags. I want to have two boxes where I can input any number and click on Show me! in order to get the result. I wrote the code below but is doesn't do anything:
<!DOCTYPE html>
<html>
<head>
<title>Interactive JS homework</title>
<style>
</style>
<script>
function calculate(){
var a = parseFloat(document.getElementById("a").value);
var b = parseFloat(document.getElementById("b").value);
document.getElementById("result") == a+b;
}
</script>
</head>
<body>
<form>
<p>
<input type="text" id="a" oninput="calculate();">
<input type="text" id="b" oninput="calculate();">
<input type="button" id="showme" value="Show me!" onclick="calculate();">
<input type="text" id="result">
</p>
</form>
</body>
Any help with where I am wrong?
Many thanks in advance!
You have to use the value property of the element. Please notice the changes in the operator used, it should be assignment (=) not compariosn (==).
document.getElementById("result").value = a+b;
I will also suggest you to assign 0 when there is no value in the element. This will prevent showing unexpected NaN as result if any of the element's value is empty.
<!DOCTYPE html>
<html>
<head>
<title>Interactive JS homework</title>
<style>
</style>
<script>
function calculate(){
var val1 = document.getElementById("a").value.trim();
var val2 = document.getElementById("b").value.trim();
var a = parseFloat(val1 == ""? 0 : val1);
var b = parseFloat(val2 == ""? 0 : val2);
document.getElementById("result").value = a+b;
}
</script>
</head>
<body>
<form>
<p>
<input type="text" id="a" oninput="calculate();">
<input type="text" id="b" oninput="calculate();">
<input type="button" id="showme" value="Show me!" onclick="calculate();">
<input type="text" id="result">
</p>
</form>
</body>
Well, it seems you merely forgot a little thing.
When reading the values of the a and b text boxes, you correctly used .value after retrieving the elements to access their value, but when you tried to set the value of result text box, you instead just compared it to the value of a+b. The == operator is for comparison, not setting a value.
Just as well, you will need to set the .value of the result text box, instead of the text box itself.
<!DOCTYPE html>
<html>
<head>
<title>Interactive JS homework</title>
<style>
</style>
<script>
function calculate(){
var a = parseFloat(document.getElementById("a").value);
var b = parseFloat(document.getElementById("b").value);
document.getElementById("result").value = a+b;
}
</script>
</head>
<body>
<form>
<p>
<input type="text" id="a" oninput="calculate();">
<input type="text" id="b" oninput="calculate();">
<input type="button" id="showme" value="Show me!" onclick="calculate();">
<input type="text" id="result">
</p>
</form>
</body>
form.html
function validate() {
var name = document.Myform.name.value;
document.write(name);
}
<html>
<head>
<script src="validations.js"></script>
</head>
<body>
<form name="Myform" onsubmit="return validate()">
Enter name: <input type="text" name="name" /><br/><br/>
<input type="submit" />
</form>
</body>
</html>
Output: undefined
After typing my name in input box it is showing undefined.
The Problem is on your input. you should change t he name=="name" to name="name". Then change your validate function to us getElementsByName. See the code below:
<html>
<head>
<script>
function validate(){
var name=document.getElementsByName('name')[0].value;
document.write(name);
}
</script>
</head>
<body>
<form name="Myform" onsubmit="return validate()">
Enter name: <input type="text" name="name"><br><br>
<input type="submit" />
</form>
</body>
</html>
dont make use of name attribute it old way of W3C standard, from long time they are suggesting make use of id attribute.
you code needs to be like this
<input type="text" id="txtname"/><br><br>
and javascript like
var name=document.getElementById("txtname").value;
You just have to fix your name=="name". In HTML we use = to assign attribute values/
function validate() {
var name = document.Myform.name.value;
document.write(name);
}
<html>
<head>
<script src="validations.js"></script>
</head>
<body>
<form name="Myform" onsubmit="return validate()">
Enter name: <input type="text" name="name" /><br><br>
<input type="submit" />
</form>
</body>
</html>
the validate function doesn't return anything as would usually be the case for this type of event hander ~ it will instead simply write the name ~ is that the desired result?
<html>
<head>
<title>form validation</title>
<script src="validations.js"></script>
<script>
function validate(e){
e.preventDefault();
var name=e.target.querySelector('input[ name="name" ]').value;
document.write( name );
return true;
}
</script>
</head>
<body>
<form name="Myform" onsubmit="return validate(event)">
Enter name: <input type="text" name="name"/><br><br>
<input type="submit" />
</form>
</body>
</html>
This question already has answers here:
Why does jQuery or a DOM method such as getElementById not find the element?
(6 answers)
Closed last year.
A small Javascript function to capitalize the contents of a text fields is as follows:
<html>
<head>
<title>capitalize</title>
</head>
<body>
<input type="text" id="uname" length="20" /><br />
<input type="submit" id="submit" value="submit" />
<script>
document.getElementById("submit").addEventListener("click",eve);
function eve(){
var uname = document.getElementById("uname").value;
uname = uname.toUpperCase();
document.getElementById("uname").value=uname;
}
</script>
</body>
</html>
Now, this is working normally, but when I change the location of the Javascript code to head tag, it's not working.
<html>
<head>
<title>key events</title>
<script>
document.getElementById("submit").addEventListener("click",eve);
function eve(){
var uname = document.getElementById("uname").value;
uname = uname.toUpperCase();
document.getElementById("uname").value=uname;
}
</script>
</head>
<body>
<input type="text" id="uname" length="20" /><br />
<input type="submit" id="submit" value="submit" />
</body>
</html>
Use a document.ready function.
When you put the code before closing the body tag, the DOM has been completely created.
Different case when you put it inside the head tag
Scripts located within the head are executed before the body has been rendered. So the elements you're trying to target don't exist yet.
Try wrapping js referencing element within window.onload event handler where js is within head element; as the #submit element is not loaded into DOM when .addEventListener attached to document.getElementById("submit")
<html>
<head>
<title>key events</title>
<script>
window.onload = function() {
document.getElementById("submit").addEventListener("click", eve);
function eve() {
var uname = document.getElementById("uname").value;
uname = uname.toUpperCase();
document.getElementById("uname").value = uname;
}
}
</script>
</head>
<body>
<input type="text" id="uname" length="20" />
<br />
<input type="submit" id="submit" value="submit" />
</body>
</html>
When in the head, your script executes before the rest of the page is loaded. Make sure you wait for your page to be loaded :
window.onload = function() {
document.getElementById("submit").addEventListener("click",eve);
function eve(){
var uname = document.getElementById("uname").value;
uname = uname.toUpperCase();
document.getElementById("uname").value=uname;
}
}
Hey guys taking a stab at my first Javascript validation but getting stuck pretty early on. I am calling a JS function from onkeyup="" but I receive the error:
Object is not a function
Code:
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js" ></script>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<h3> My Sign Up Form</h3>
<form name="signup">
<label>First Name<input type="text" name="fname" onkeyup="fname()"/></label><div id="fnameVal"></div><br>
<label>Last Name<input type="text" name="lastname" onkeyup="fourchars();"/></label><div id="lnameVal"></div><br>
<!--<label>Email<input type="text" name="email"/></label><div id="email"></div><br>
<label>Password<input type="password" name="password"/><div id="password"></div></label><br>
<label>ConfirmPassword<input type="password" name="confirmpassword"/><div id="confirmpassword"></div></label><br>-->
<label><input type="submit" value="Submit"/></label>
</form>
</body>
<script>
function fname(){
alert('jjjj');
}
</script>
</html>
you can't have your function name same as your control name. i.e. fname & fname()
<label>First Name<input type="text" name="fname" onkeyup="validateFname()"/></label><div id="fname"></div>
OK, Try something like this.
replace your onkeyup to this. I know it is the same code but sometimes it works when you relace you code by the same code form an other site. BTW it works fine if I test is on a site.
onkeyup="fname()"
Raname your function to be different from the input name.
e.g.
<script>
function valname(){
alert('jjjj');
}
</script>
</head>
<body>
<h3> My Sign Up Form</h3>
<form name="signup">
<label>First Name<input type="text" name="fname" onkeyup="valname()"/></label><div id="fnameVal"></div><br>
It seems as fname is a reference to your element in your form. Try changing the name of the function or the name of element.
function fnameFunc() {
alert('jjjj');
}
And the HTML
<input type="text" name="fname" onkeyup="fnameFunc()"/>
You can use jquery on keyup
$(document).ready(function() {
$('body').on("keyup", "input[name=fname]", function() {
alert($(this).val());
// do your stuff
});
});
JSFIDDLE DEMO