Does this JS Code work as expected?

Question

Every 3 seconds I make an AJAX POST request to get the status of a process. This works great.

When the process reaches 100% a call back function executes(indicated below) to add new elements to the page and then it cancels the setTimeout method that use to continuously get the progress every 3 seconds. However, I have been told by my users it sometimes fails to cancel and the new elements are not added to the page and I've been that it get stuck at showing "100%".

I have tested this again and again and it never gets stuck for me. The code also looks ok, but my JavaScript skills are not great so I was hoping someone could point out if there is potential of this problem happening?

I have commented the code, apologies its very long. I have tried to reduce it.

function convertNow(validURL){

    startTime = setTimeout('getStatus();', 6000); 
       //AJAX CALL TO RUN PROCESS
       $.ajax({
       type: "GET",
       url: "main.php",
       data: 'url=' + validURL + '&filename=' + fileNameTxt,
       success: function(msg){
       //ON SUCCESS CLEAR SETTIMEOUT AND SHOW ELEMENTS (text)
       clearTimeout(continueTime);
       clearTimeout(startTime);    
     $("#loading").hide("slow");
     $("#done").html("Done");   
       }//function

     });//ajax

}//function convertNow

function getStatus(){
     //AJAX CALL TO GET STATUS OF PROCESS
     $.ajax({
     type: "POST",
     url: "fileReader.php",
     data: 'textFile=' + fileNameTxt,
     success: function(respomse){
     textFileResponse = respomse.split(" ");
     $("#done").html("Processing...");
     }
     });//ajax
     clearTimeout(continueTime);

     if(textFileResponse[0]=='100.0%'){
      clearTimeout(continueTime);
     }
     else{
         clearTimeout(startTime);
      continueTime = setTimeout('getStatus();', 3000); 
     }
}

Answer 1

There's probably a parsing error in the textFileReponse[0]=='100.0%' in some edge cases, with the value in the response not equaling exactly 100.0% (maybe there's extra whitespace, or maybe there are some minor differences on some platforms, etc...). This would cause the code to fall through to the else {} block, and your getStatus function would be queued up again.

EDIT: Given the thread in the comments, it's also an equal likelyhood that there's a race condition going on between the two blocks of Ajax code. (just putting this here for the benefit of readers). END EDIT

What you probably want, in addition to resolving the parsing, however, is to use setInterval(), with only one timer, instead of a startTime and continueTime timer. setTimeout executes only once, whereas setInterval repeats every x milliseconds, so you'd need only one. To cancel a setInterval, use clearInterval.