I tried to do something like this :
var msg = $.get(\"my_script.php\");
I thought msg would be set to the text returned by my_script.php,i.
After some testing, I ended up finding a solution.
I need the call to be synchronous, $.get shorthand function is always asynchonous, so I will need to use $.ajax, like this:
var msg = $.ajax({type: "GET", url: "my_script.php", async: false}).responseText;
I don't think there is a better way to do this, thanks for your answers.