jQuery return ajax success function results

Question

I need to return true or false to my alert() from the results of an ajax success function. However, I'm having problems since the alert() result is always 'undefined'...any ideas on how to fix this?

I have DoAjax as it's own function because I call it multiple times within the .js file.

var val = '12345';  
alert( DoSerialVerification( val ) ); //this returns 'undefined' regardless of cType.length

function DoSerialVerification( piVal ){
    var fSuccess = function( oData ){
        var cType = oData.type
        if( cType.length > 0 ){
           alert( cType );                  //with piVal = 12345 cType will return 'MODULE'
           $('#dialog-1').attr('type', cType);
           return true;
        } else {
           return false;
        }
    };
    DoAjax({ Action: "DoSerialVerification", Value: piVal }, fSuccess );
}

function DoAjax( pAjaxParams, pSuccess ){
    $.ajax({url        : 'procedures?',
            data       : pAjaxParams,
            async      : false,
            type       : "POST",
            dataType   : "json",
            error      : function(oD,oT,oE){ alert( oD+'\n'+oT+'\n'+oE ) },
            success    : pSuccess
    });
}

@IAbstractDownVoteFactory - yes procedures is returning 'MODULE' — sadmicrowave
– sadmicrowave, Commented Sep 16, 2011 at 12:14

ivan · Accepted Answer · 2011-09-15 21:58:02Z

1

you need to return something from the DoSerialVerification function... modified DoSerialVerification function:

function DoSerialVerification( piVal ){
    // here
    var result = false;

    var fSuccess = function( oData ){
        var cType = oData.type
        if( cType.length > 0 ){
           alert( cType );                  //with piVal = 12345 cType will return 'MODULE'
           $('#dialog-1').attr('type', cType);

           //here
           result = true;
        }
    };
    DoAjax({ Action: "DoSerialVerification", Value: piVal }, fSuccess );

    //here
    return result;
}

edited Sep 15, 2011 at 21:58

answered Sep 15, 2011 at 21:34

ivan

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2 Comments

ivan Over a year ago

@Elliot Nelson: jQuery supports synchronous ajax, "async: false" option is used for that.

ivan Over a year ago

'cause DoSerialVerification returned nothing but it had to. i guess you expected nested fSuccess function to propagate its result to DoSerialVerification... but no, result of fSuccess is not propagated.

Elliot Nelson · Accepted Answer · 2011-09-15 21:27:17Z

0

What you're trying to do isn't possible: calling AJAX is an asynchronous process, your function DoAjax will return before the response is ever received from the server. That is why you are providing callbacks: once the server returns a response, it'll enter either your error callback or your success callback, depending on the result.

Change this:

alert( DoSerialVerification( val ) );

To this:

DoSerialVerification(val);

And then move your alert call into your "fSuccess" function.

answered Sep 15, 2011 at 21:27

Elliot Nelson

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