Question

I am busy developing a chrome extension.

What it will do:

1. Get data from a PHP page (XMLHttpRequest)

2. Split the result variable using .split

3. And when someone clicks on a div, it will call a function to insert a css file with that name I got in number 1.

My problem:

Well nothing happens when I click that button. It works when I used the variable, “newvar”, instead of the variable, “currenttheme” from the XMLHttpRequest. I tried converting it to a string as well using .toString. Oh, alerting the variable does work and gives exactly the same response as newvar.

My code: (Sigh!)

//My XMLHttpRequest
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    user_data = xmlhttp.responseText;
    window.user_data = user_data;
    processdata();
    }
  }
xmlhttp.open("GET","http://localhost:8888/myphppage.php",true);
xmlhttp.send();

function processdata() {
//split result variable from PHP
var downdata = user_data.split('|||||');
var installedthemes = downdata[0];
currenttheme = downdata[1].toString();
window.currenttheme = currenttheme.toString();
}

function click(e) {
  newvar = "001";
  //insert css - works with variable newvar but not with this one
  chrome.tabs.insertCSS(null,
  {file:currenttheme + ".css"});
  //alerting the variable works, exactly the same as newvar
  alert (currenttheme);
}

document.addEventListener('DOMContentLoaded', function () {
   var divs = document.querySelectorAll('div');
  for (var i = 0; i < divs.length; i++) {
    divs[i].addEventListener('click', click);
  }
});

Answer 1

window.user_data = user_data;// <- not required. user_data = xmlhttp.responseText implies user_data is global to this window.
window.currenttheme = currenttheme.toString(); <<- not required too

also downdata[1] IS a string so replace

currenttheme = downdata[1].toString();

with

currenttheme = downdata[1];

If this doesn’t help, try alert(currenttheme); and see if you are getting the required theme name, because sometimes PHP can throw errors and die which may not produce a “|||||”. Check the php output and alert the xmlhttp.responseText too to see if everything is OK.