How to send ajax request when I process data from request before?

At start of my app I need to send three ajax get (Dojo xhrGET ) requests, but problem is that I need to send second when I process data from first and send third when I process data from second ( order is important ! ). I put this requests one behind other but it sometimes doesn't work. How to 开发者_开发知识库synchronize and solve this, is there any way to lock or wait like in Java ?

If you're using 1.6, check out the new Promises API (returned by dojo.xhrGet), or use deferreds in 1.5. They provide a 'neater' way to achieve this.

Essentially you can write:

dojo.xhrGet({
    url: './_data/states.json',
    handleAs: 'json'
}).then(    
    function(response) {
        // Response is the XHR response
        console.log(response);
        dojo.xhrGet({
            url: './_data/'+response.identifier+'.json',
            handleAs: 'json'
        }).then(
            function(response2) {
                // The second XHR will fail
            },
            // Use the error function directly
            errorFun
        )
    },
    function(errResponse) {
        // Create a function to handle the response
        errorFun(err);
    }
)

var errorFun = function(err) {
    console.log(err);
}

See http://dojotoolkit.org/documentation/tutorials/1.6/deferreds/ and http://dojotoolkit.org/documentation/tutorials/1.6/promises/ for more information

You can use option sync = true, and put the request one behind other. With this, 3rd will be sent after 2nd after 1st. Or you can begin send 2nd request after 1st is done by using load function. Example:

dojo.xhrGet({ //1st request
    load: function(){
        dojo.xhrGet({ //2nd request
            load: function(){
                dojo.xhrGet({ //3nd request

                });
            }
        });
    }
});

For more information: http://dojotoolkit.org/reference-guide/dojo/xhrGet.html

Can we make the second ajax request in the success callback method of the first request: $.ajax({

'type' : 'get', // change if needed
'dataType' : 'text', // data type you're expecting
'data' : { 'className' : divClass },
'url' : url,
'success' : function(newClass) {
  //make the second ajax request...
}

});

And do the same thing for the third request.