setInterval not working (firing only once) in Google Chrome extension

Question

Just as the title says: setInterval is only firing its callback once.

manifest.json:

{
    //...
    \"content_scripts\" : [{
                 


        

Answer 1

setInterval isn't working at all.

The first argument should be a function, you are passing it the return value of alert() which isn't a function.

Use the three argument version:

setInterval(function,time,array_of_arguments_to_call_function_with);
setInterval(alert,2000,['only shown once']);

Answer 2

The way you wrote it it's wrong:

setInterval() wants a function and a numerical value: setInterval(function(){//your code}, timeInterval).

Answer 3

setInterval(function() { alert('only shown once') },2000);

You need to pass a function reference like alert and not a return value alert()