bookmarklet中的Ajax：已完成操作但未给出答案

Question

I'm trying to do my own bookmarklet and I already tried to read some response in SO but nothing to answer the weird reaction I got from my script.

I'm doing an AJAX call from my bookmarklet, so I do the little trick :

var newScript = document.createElement("script");
newScript.type = "text/javascript";
newScript.src = "http://example.com/urlToMyJS.js";
document.body.appendChild(newScript);
void(0);

And the urlToMyJS.js is like this :

var u = 'http://example.com/scriptToCall.php';
var request = new XMLHttpRequest();
request.open("GET", u, true);
request.onreadystatechange = function() {
  var done = 4, ok = 200;
  if (request.readyState == done && request.status == ok) {
    if (request.responseText) {
      alert(request.responseText);
    }
  }
};
request.send(null);

The weird part is :

• The javascript is always launched and scriptToCall.php is always called too (it logs every hit)
• The alert shows the responseText when I click on the bookmarklet on example.com
• Sometimes, on other sites, the alert shows nothing (but still appears)
• Some other times, the alert doesn't even show... (but I still have the log hit...)

Do you have any idea why it does that? And if yes, do you have any idea how I could make it always show the responseText?

Answer 1

Well, finally, I used another trick :

var newScript = document.createElement("script");
newScript.type = "text/javascript";
newScript.src = "http://example.com/scriptToCall.php";
document.body.appendChild(newScript);
void(0);

This way (the PHP is sending a javascript header), no more AJAX. It was nonsense in my case since both file were in the same server/folder, 1 movement instead of 2!

Anyway, thanks bobince for all the details I might use in the future !