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
.
{
"name":"Facebook",
"version":"1.0",
"description":"My Facebook Profile",
"manifest_version":2,
"browser_action":{
"default_icon":"google-plus-red-128.png",
"default_popup":"hello.html"
}
}
Here is the code for the html page
<!DOCTYPE html>
<html>
<head>
<script>
var a=0;
function count()
{
a++;
document.getElementById("demo").innerHTML=a;
return a;
}
</script>
</head>
<body>
<p id="demo">=a</p>
<button type="button" onclick="count()">Count</button>
</body>
</html>
I want the extension to show me the value of a and increment it by one each time I click on the extension or the button
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.