CODEWITHSUNDEEP
javascriptajax
Babiker
Babiker

Reputation: 18798

How to check if an ajax function is busy from a previous call

How to check if an ajax function is busy from a previous call? How can i prevent the call to an ajax function if it's readyState != 4 yet from a previous call?

Upvotes: 4

Views: 1630

Answers (2)

Joop
Joop

Reputation: 2839

The question is if you want to skip the Ajax call if the previous call is still busy or not? If you want to skip it the solution is easy and the one of Matthew perfectly suits your need. However if you want to start executing the call after the previous one is finished, that's a whole different story. I can provide you with some code if needed.

Have been working on a solution:

<script language="javascript" type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/prototype/1.6.0.3/prototype.js"></script>
<script language="javascript" type="text/javascript">
var requestInProcess = false;
var timer = null;

function requestSomeStuffA() {
    var responseHolder = $("responseHolder");

    new Ajax.Request(
        "http://webservicelocation/",
        {
            method: 'GET',
            contentType: 'application/json; charset=utf-8',
            onCreate: function() { 
                requestInProcess = true;
            },
            onSuccess: function(transport) {
                //do something with the transport
            },
            onFailure: function(error) {
                //throw a nice exception
            },
            onComplete: function() {
                requestInProcess = false;
            }
        }
    );
}

function requestSomeStuffB() {
    clearTimeout(timer);

    if(requestInProcess) {
        //wait again for a while
        timer = window.setTimeout("requestSomeStuffB()", 10); //timeout in miliseconds
    }
    else{
        //execute the next Ajax request
    }
}
</script>

When you call first requestSomeStuffA and then requestSomeStuffB, requestSomeStuffB will wait for requestSomeStuffA to be finished. Hope this is useful for you.

Upvotes: 0

Matthew Flaschen
Matthew Flaschen

Reputation: 284836

You can use a boolean and an appropriate onreadystatechange functoin;

var inprogress = true;
ajaxRequest = ...
ajaxRequest.onreadystatechange = function(){
    if(ajaxRequest.readyState == 4){
        inprogress = false;
    }
}

Upvotes: 5

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