I'm just starting out in Javascript, and I'm trying to put my scripts in a separate file. They work just fine when they're in the html file, but as soon as I move them to their own separate file it stops working.
Here's my html file:
<!DOCTYPE html>
<head>
<meta lang = "en">
<link rel="stylesheet" type="text/css" href="css/mainStyle.css">
<script src="js/script1.js"></script>
<title>Web Dev Practice</title>
</head>
<body>
<h1>First JavaScript Example</h1>
<button type="button" onclick="changeText()">ClickMe!</button>
<p id="demo">This is just a test.</p>
</br>
</br>
<h1>Second JavaScript Example</h1>
<img id="lightBulb" onclick="changeImage()" src="res/img/pic_bulboff.gif" width="100" height="180">
<p>Click the light bulb to turn it on or off.</p>
</body>
</html>
And here's my js file:
<script>
function changeText(){
var string_first = "This is just a test.";
var string_second = "Woah, it actually works!";
if(document.getElementById("demo").innerHTML == string_first){
document.getElementById("demo").innerHTML = string_second;
} else{
document.getElementById("demo").innerHTML = string_first;
}
}
<script>
function changeImage(){
var image = document.getElementById('lightBulb');
if(image.src.match("bulbon")){
image.src = "res/img/pic_bulboff.gif";
}
else{
image.src = "res/img/pic_bulbon.gif";
}
}
</script>
The <script> tags are html things, not javascript, so you don't need (and can't have) them in your external files. What browser are you using? Many have a built in console that can help you see what errors, if any, your page is throwing.
Related
I'm making a HEX to RGB colour converter and I have done all the things I think you are suppose to do and that is my JS code and HTML code
HTML
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style.css">
<title>Colour Converter</title>
</head>
<body>
<center>
<h1>Hex - RGB</h1>
<input id="hex">
<input id="rgb">
<script src="Main.js"></script>
</center>
</body>
</html>
Javascript
var HexInput = document.getElementById("hex");
var RGBInput = document.getElementById("rgb");
HexInput.addEventListener("input",ToHex);
function ToHex() {
console.log("Test")
}
and I get this Error
Uncaught TypeError: Cannot read property 'addEventListener' of null
at Main.js:3
I just got started learn JavaScript and I'm fairly new
You should make a few changes:
First, you need to run your script after the entire DOM has loaded. If you run your script before the DOM has fully loaded, then your document.getElementById won't be able to find the element and will return null.
Second, you also need to change ToHEX() to ToHEX in your addEventListener. The former was executing ToHEX immediately and returning nothing. The latter will pass the function to the addEventListener. Edit: It looks like you just updated your question to address this.
Here is the corrected code:
document.addEventListener("DOMContentLoaded", function(event) {
var HexInput = document.getElementById("hex");
var RGBInput = document.getElementById("rgb");
HexInput.addEventListener("input",ToHEX);
function ToHex() {
console.log("Test")
}
});
Lastly, you should also move your <script src="Main.js"></script> line back into the header -- it doesn't need to be inserted after your HTML. Including the script after your HTML doesn't mean that it will run after the page has loaded.
This code seems to work. I fixed code order and typo error.
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style.css">
<title>Colour Converter</title>
</head>
<body>
<center>
<h1>Hex - RGB</h1>
<input id="hex">
<input id="rgb">
<script>
function ToHex() {
console.log("Test");
}
var HexInput = document.getElementById("hex");
var RGBInput = document.getElementById("rgb");
HexInput.addEventListener("input", ToHex);
</script>
</center>
</body>
</html>
Thanks Bassem Rabia It works
HTML
<!doctype html>
<html lang="en">
<head></head>
<body>
<input id="hex">
<input id="rgb">
<script src="main.js"></script>
</body>
</html>
JavaScript
document.addEventListener("DOMContentLoaded", function(event){
function toHex(){
console.log("Test");
}
var HexInput = document.getElementById("hex");
var RGBInput = document.getElementById("rgb");
HexInput.addEventListener("input", toHex);
});
Also, you have 2 mistakes in this line
HexInput.addEventListener("input",ToHEX());
the name of the method is misspelled
When you attach the event handler you just pass the reference to the function and not the invocation
So this would be the correct one
HexInput.addEventListener("input",ToHex);
http://prntscr.com/ic1vom
<!doctype html>
<html lang="en">
<head></head>
<body>
<input id="hex">
<input id="rgb">
<script src="main.js"></script>
</body>
</html>
main.js
document.addEventListener("DOMContentLoaded", function(event){
function toHex(){
console.log("Test");
}
var HexInput = document.getElementById("hex");
var RGBInput = document.getElementById("rgb");
HexInput.addEventListener("input", toHex());
});
I am trying to display youtube audio without video with the below code so I am changing the video id but it is playing the same id again and again.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>About</title>
<script type="text/javascript">
function val1(val)
{
document.getElementsByTagName("div")[0].setAttribute("data-video", val);
alert(val);
}
</script>
</head>
<body onload="val1('WKV_z36pVAk')">
<h3 style="color:#0066dd">Hello</h3>
<center>
<div data-video="8IYzyTYucKQ"
data-autoplay="0"
data-loop="1"
id="youtube-audio">
</div>
</center>
<button>change</button>
</body>
<script src="https://www.youtube.com/iframe_api"></script>
<script src="https://cdn.rawgit.com/labnol/files/master/yt.js"></script>
</html>
Not quite sure what you are trying to create, but this might head you into the right direction.
You can reload the specific element in a kind of hacky way using this code
function reload(vidId){ <-- Added a parameter
var container = document.getElementById("youtube-audio");
container.setAttribute("data-video", vidId); <-- Added line to change data-video
var content = container.innerHTML;
container.innerHTML= content;
}
And then add this to your HTML
<button onclick="reload('8IYzyTYucKQ')">Reload</button> <-- Added the parameter to what the `data-video` should be changed
I wan't to inject a .css on a page by clicking a button on my extensions!
Here is the popup.html:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="css/popup.css">
<script type="text/javascript" src="black.js"></script>
<script type="text/javascript" src="white.js"></script>
</head>
<body style="width: 400px">
<h1>test v1.0.0</h1>
<hr ></hr>
<input type="button" onclick="black" value="Black"/>
<input type="button" onclick="white" value="White"/>
</body>
</html>
And here is the black.js (white.js is almost the same):
function black() {
var browserListener = function(tab) {
chrome.tabs.insertCSS(tab.id, {
file: "css/black.css"
});
}
}
I don't know why but it's not working.
You can also try:
var blackCss = document.createElement('link');
blackCss.src = "css/black.ss";
blackCss.rel = "stylesheet";
document.head.appendChild(blackCss);
Of course, you can wrap that in a function and make the src path dynamic.
There are lots of ways of doing this literally LOTS ive come up with 1 solution but now that i think of it its probably not best but it works.
<!DOCTYPE html>
<html>
<head>
<title>Test</title>
</head>
<body>
<h1>test v1.0.0</h1>
<input id="black" type="button" value="Black"/>
<input id="blue" type="button" value="Blue"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script>
(function(){
$('#black').on('click', function(){
var location = 'black.css';
var link = $("<link rel='stylesheet' href='"+ location +"'>");
$('head').append(link);
});
$('#blue').on('click', function(){
var location = 'blue.css';
var link = $("<link rel='stylesheet' href='"+ location +"'>");
$('head').append(link);
});
})();
</script>
</body>
</html>
You could go so much further with this and make it 1 function that just changes the value of the href tag on the css link. but this also works fine. I wouldn't recommend using this exact code but im hoping you get what im trying to show here
I'm trying to create a range of numbers in a dropdown form using JavaScript.
However, it looks like
…and it does not show any options and clicking on the arrow does not pop up more options. I already checked that my path is correct.
I tried it in JSFiddle and it works but not when I put it in my HTML.
I'm going crazy on why this is not working.
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="stylesheet" href="../stylesheets/main.css">
<script type="text/javascript" src="../assets/main.js"></script>
</head>
<body id="gradient">
<div id="down" class="center">
<p >Word Size</p>
<select id="length">
</select>
</div>
</body>
</html>
main.js
var select = document.getElementById('length');
for (var i = 0; i<= 24; i++){
var option = document.createElement('option');
option.value = i;
option.innerHTML = i;
select.options.add(option);
}
The problem is that when main.js script is parsed and executed, there is no element with id length yet in DOM. The simplest solution is to move your script to the very end of body tag:
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="stylesheet" href="../stylesheets/main.css">
</head>
<body id="gradient">
<div id="down" class="center">
<p >Word Size</p>
<select id="length"></select>
</div>
<script type="text/javascript" src="../assets/main.js"></script>
</body>
</html>
The reason why it works in jsFiddle, is because it's configured so that script section is executed on window.onload event (in the right side-panel, dropdown "onLoad"). Of course, you could do the same, e.g. in main.js:
window.onload = function() { /* previous main.js code */};
In this case you would not need to move script anywhere.
I have the following code that works:
<html>
<head>
<script>
function loaded(){
oFormElement = document.forms['test form'].elements["txtStatus"];
oFormElement.value = "just loaded";
}
</script>
</head>
<body onload="loaded()">
<p>my first socket.io test</p>
<form id = "test form">
<input type="text" id ="txtStatus" value="">
</form>
</body>
</html>
now, if I include the reference to socket.io, it stops working
<html>
<head>
<script src="socket.io/socket.io.js">
<script>
function loaded(){
is this because socket.io handles from elements in it's own way, or is because the browser cannot find socket.io ? Is there any way to debug this/fix this ?
You need to close the first <script> tag...
<html>
<head>
<script src="socket.io/socket.io.js"></script>
<script>
function loaded(){
// ...