This question already has answers here:
Code working in jsFiddle but not in browser
(2 answers)
Closed 9 years ago.
I am having a problem with my JavaScript, when I put it into JSFiddle it works fine. But it wont work locally? Here is the fiddle: http://jsfiddle.net/4Ukkz/
var String = "preacher preacher, 5th grade teacher";
document.getElementById('text').innerHTML=String;
So the problem is. In the JSFiddle, the text will display, But locally nothing will display.
Note. It works in the fiddle. but not on my computer
In JSFiddle, your code is automatically wrapped with
window.onload = function() {
// your code
};
This is necessary because in your code, script.js is included above <div id="text"></div>. If you don't wait until that element exists, document.getElementById('text') will return null and the attempt to set innerHTML will fail.
The solution is to wrap your code as above or move your script tag below the div.
May be you don't have a script.js file with the javascript code you pasted in the fiddle?
And move the script element after your body. So your JavaScript code runs after all the elements in the body have been created.
So something like this:
<html>
<title>hi</title>
<head>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>
<div id="text"></div>
</body>
<script type='text/javascript' src='script.js'></script>
</html>
Related
This question already has answers here:
Why does jQuery or a DOM method such as getElementById not find the element?
(6 answers)
Closed 8 months ago.
I wanted to use Dart to replace JavaScript.
But it's not an advanced project. It's just a matter of dynamically changing a few elements within a single page.
For starters, I wrote the following HTML code and Dart code to find the element based on its ID and display the text in the console.
<!-- index.html -->
<html>
<head>
<title>Test</title>
<script type="text/javascript" src="index.js"></script>
</head>
<body>
<p id="first-paragraph">Target.</p>
</body>
</html>
// index.dart
import 'dart:html';
void main() {
print(querySelector('#first-paragraph')?.innerText);
}
The following command converts the file to a JavaScript file.
dart compile js index.dart -o index.js -O0
However, when I open the HTML file, the console shows null.
The first code in Dart Pad HTML mode, which is very similar to the above code, appears to work (on Dart Pad).
Why can't my code find the element?
Thanks.
Thank you for your comments. I remembered from your comments and was able to get it to work as expected by placing the script readout at the end of the body element or using window.addEventListener. I am ashamed to say that I forgot to do something so simple.
<!-- index.html -->
<html>
<head>
<title>Test</title>
</head>
<body>
<p id="first-paragraph">Target.</p>
<script type="text/javascript" src="index.js"></script>
</body>
</html>
or
// index.dart
import 'dart:html';
void main() {
window.addEventListener('DOMContentLoaded', (event) {
print(querySelector('#first-paragraph')?.innerText);
});
}
This question already has answers here:
Why does jQuery or a DOM method such as getElementById not find the element?
(6 answers)
Closed 6 years ago.
I am very new to jQuery, literally just trying to get it to work for the first time. Only the alert box works, but none of the other very simple methods I am trying out. Here are the files:
HTML:
<!DOCTYPE HTML>
<html>
<head>
<title>jquery</title>
<script type="text/javascript" src="jquery-3.1.0.min.js"></script>
<script type="text/javascript" src="myJavaScript.js"></script>
</head>
<body>
<h1 id="title">This is a title</h1>
<p> This is some sample text.</p>
</body>
</html>
JavaScript file:
$(document).ready(function (){alert("this works!")});
$("#title").text("but this is not not working");
As you can see the example can't be simpler. I have off course downloaded the jquery-3.1.0.min.js file and put it in the same folder as the html. If I comment out the link, the alert stops working, so I now the file is being referenced OK. Why is the second line of jQuery not working? Many thanks, P
Because the DOM(the entire structure of your application) isn't loaded yet. You need to use a $(document).ready(makes sure the DOM is loaded before running jQuery code) or an event handler to make the change visible.
This question already has answers here:
JavaScript getElementByID() not working [duplicate]
(3 answers)
Closed 7 years ago.
The Problem
I'm trying to display the output of a function to a div, but i can't figure out why it isn't displaying. How can i fix this so that it displays properly?
What i've tried so far
I've copied a document.getElementById statement from another codeblock i wrote that is functioning , and checked it for any typos etc. All seems well there.
I googled innerHTML to be sure that I was using it correctly.
Also changed the document.etc line to document.write to ensure the function was working properly, it output properly.
My Code
<html>
<head>
<script type="text/javascript">
function parameters(one, two) {
document.getElementById('output').innerHTML=(one + two);
}
parameters("coding" , "coffee");
</script>
</head>
<body>
<div id="output"></div>
</body>
</html>
The problem is that you're trying to use the div#output before it's even loaded by the browser.
There are two simple solutions for this:
First
Put the <script> tag after the div#output, so it will be already loaded.
<html>
<head>
</head>
<body>
<div id="output"></div>
<script type="text/javascript">
function parameters(one, two) {
document.getElementById('output').innerHTML=(one + two);
}
parameters("coding" , "coffee");
</script>
</body>
</html>
Second
Put your Javascript code inside the DOMContentLoaded event, so it will only be called after all the DOMElements are loaded in your page.
<html>
<head>
<script type="text/javascript">
function parameters(one, two) {
document.getElementById('output').innerHTML=(one + two);
}
document.addEventListener('DOMContentLoaded', function() {
parameters("coding" , "coffee");
});
</script>
</head>
<body>
<div id="output"></div>
</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 9 years ago.
I'm trying to get the element with getElementById(), but it returns null even though the element exists. What am I doing wrong?
<html>
<head>
<title>blah</title>
<script type="text/javascript">
alert(document.getElementById("abc"));
</script>
</head>
<body>
<div id="abc">
</div>
</body>
You have to put this in a document load event. The DOM hasn't gotten to abc by the time the script is executed.
Your script runs before the DOM has been loaded. To fix this you can place your code in the window.onload function like so:
window.onload = function() {
alert(document.getElementById("abc"));
};
An alternative is to place your script right before the closing </body> tag.
If you don't want to attach to the load event then simply put your script at the bottom of the body, so it will execute at the end-
<html>
<head>
<title>blah</title>
</head>
<body>
<div id="abc">
</div>
<script type="text/javascript">
alert(document.getElementById("abc"));
</script>
</body>
</html>
This is because the script runs before the page has rendered.
For proof add this attribute to the body tag:
<body onload="alert(document.getElementById('abc'));" >
But it doesn't exist, not at that point in the HTML. HTML documents are parsed top-to-bottom, just like programs run. The best solution is just to put your script tag at the bottom of the page. You could also attach your JavaScript to the onload event.
This question already has answers here:
when and where to put javascript in html
(7 answers)
Closed 9 years ago.
the thing is i'm unable to figure out where to embed javascript in html page whether in head section or body section.
example 1:
<html>
<head>
<title>events</title>
<script>
document.getElementById("b").onclick=function(){displayDate()};
function displayDate()
{
document.getElementById("demo").innerHTML=Date();
}
</script>
</head>
<body>
<p id="demo"></p>
<button id="b">new</button>
</body>
</html>
in the above example I placed script tags in head section but it is not working.
example: 2
<html>
<head>
<title>events</title>
<script>
function upper()
{
var x=document.getElementById("t");
x.value=x.value.toUpperCase();
}
</script>
</head>
<body >
enter some text:<input type="text" id="t" onChange="upper()"/>
</body>
</html>
in the second example I placed the javascript in head section it is working properly.first example demonstrates that on clicking a button date will be displayed in the second example in a text box when data is entered and if we come out of the box the letters in the box will we converted to uppercase.
To have it more readable I prefer to always place JavaScript in the head section. If you need to access elements from there, use the window.onload event:
<head>
<title>events</title>
<script type="text/javascript">
window.onload = function() {
document.getElementById("b").onclick = function() {
displayDate();
};
};
function displayDate()
{
document.getElementById("demo").innerHTML=Date();
}
</script>
</head>
This would work just fine.
Your second example worked because you just defined a function, you didn't try to access any element.
You can put it in the head. The problem is that your examples are not the same. The first one doesn't work because the current date is retrieved by calling Date(), when it should be new Data().getDate(). The second example works because the code is valid.
The problem you're running into is that you're trying to reference an element before it is loaded into the DOM.
When you're putting the script in the HEAD tag, the dom hasn't been loaded yet and the document.getElementById won't find what you're looking for.
You have a few different options to deal with this. You can put the script at the end of the page, which will work for your small example here.
Probably a better option is to take a look at learning/using jquery or another js utility. Jquery makes it easy to solve this issue by giving you a "ready" event. This ready event will be triggered when the DOM is fully loaded. So:
$(document).ready(
function()
{
$("#demo").html((new Date()).toString());
});
Is all you really need. With this approach, it doesn't matter where the script it on the page.