javascript - Problem: XMLHttpRequest - handle server connection lost - Stack Overflow

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How do I handle the scenario where I making a synchronous request to the server using XMLHttpRequest and the server is not available?

xmlhttp.open("POST","Page.aspx",false);
xmlhttp.send(null);

Right now this scenario results into a JavaScript error: "The system cannot locate the resource specified"

How do I handle the scenario where I making a synchronous request to the server using XMLHttpRequest and the server is not available?

xmlhttp.open("POST","Page.aspx",false);
xmlhttp.send(null);

Right now this scenario results into a JavaScript error: "The system cannot locate the resource specified"

• javascript
• xmlhttprequest

Share Improve this question Follow asked Dec 18, 2008 at 8:43 coder_brocoder_bro 10.8k1414 gold badges6060 silver badges9090 bronze badges 1

• geekswithblogs/lorint/archive/2006/03/07/71625.aspx heres a tutorial for doing it for a single request. – fasih.rana Commented Dec 18, 2008 at 9:20

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3 Answers 3

Sorted by: Reset to default 3

Ok I resolved it by using try...catch around xmlhttprequest.send

:

xmlhttp.open("POST","Page.aspx",false);              
       try
       {
       xmlhttp.send(null);
       }
       catch(e)
       {
            alert('there was a problem municating with the server');
       }       

Try the timeout property.

xmlHTTP.TimeOut= 2000 

You don't check for properly returned status. By the code you gave you are doing a GET request. To properly check the status of your request, you must create an event handler for the onreadystatechange event and then inside it check if the readyState property is equal 4 and then inside the method if the status is 200.

You can find a detailed explanation here :Ajax Tutorial by Mozilla

  
xmlhttp.onreadystatechange=function()

xmlhttp.open("GET","Page.aspx",false);
{
  if (xmlhttp.readyState==4) 
  {
     if (xmlhttp.status==200)
     {
       //Ajax handling logic
     }
  }
}
xmlhttp.send(null);

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