I have created a JavaScript variable and when I click on the button it should increment by 1, but its not happening.
Here\'s manifest.json
.
Change your onclick
:
onclick="count"
Or change your count function to something like this:
function count()
{
var demo = document.getElementById("demo");
return function() {
demo.innerHTML = ++a;
}
}
Here is a nice demo I put together:
Code (this assumes that you add id="the_button"
to your button):
window.onload = function () {
var button = document.getElementById("the_button");
button.onclick = count();
function count() {
var a = 0;
var demo = document.getElementById("demo");
return function () {
demo.innerHTML = ++a;
}
}
}
Demo: http://jsfiddle.net/maniator/ck5Yz/
Your code is not working because it violates the default Content Security Policy. I've created a screencast of one minute to show what's wrong:
First, I've shown how to debug the problem. Right-click on your popup button, and click on "Inspect popup". After doing that, you will see the following error message:
Refused to execute inline script because it violates the following Content Security Policy directive: "script-src 'self' chrome-extension-resource:".
This explains that your code is not working, because it violates the default CSP: Inline JavaScript will not be executed. To solve the problem, you have to remove all inline JavaScript from your HTML file, and put it in a separate JS file.
The result is shown below:
hello.html
(popup page)<!DOCTYPE html>
<html>
<head>
</head>
<body>
<p id="demo">=a</p>
<button type="button" id="do-count">Count</button>
<script src="popup.js"></script>
</body>
</html>
popup.js
var a=0;
function count() {
a++;
document.getElementById('demo').textContent = a;
}
document.getElementById('do-count').onclick = count;
Note that I've replaced innerHTML
with textContent
. Learn to use textContent
instead of innerHTML
when you intend to change the text. In this simple example it does not matter, but in more complex applications, it might become a security issue in the form of XSS.