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Using Global var to cycle through AJAX doesn't work

in Using jQuery • 7 years ago

I am trying to call AJAX three maybe four times to get information from my DB. Can't get "global" var mapAddress
to return. I've tried to position the function in various locations but can't get it right. I'm sure this has to do with asynchronous functioning but still don't understand it.

Thanks for help,

R
<script type="text/javascript">

var recId="";
var mapAddress=""; // declaring here to create global var

// ==================================================================
// =========== lots of other code including code
// =========== that triggers $('.map').click function below =========
// ==================================================================

$('.map').click(function () {

// ======== there may be two addresses to process =========
// ======== home address and work address ==============

var phaseFlag=1;
// MULTIPLE CALL TO AJAX
// first phase query the DB to SELECT all address, city, state data ======
// phase two would be a call to SELECT home address info =================
// phase three would be a call to SELECT work address info ==============

mapAddress=myAjaxCallGeo(phaseFlag);

// =========== do stuff with mapAddress ===============

alert("ajax "+mapAddress); // mapAddress is undefined

});

</script>

<script type="text/javascript">

function myAjaxCallGeo(phaseFlag) {

var request = $.ajax({
    url: "getLatLong2.php",
    type: "GET",
    data: {"id":choice, "phase":phaseFlag},
    dataType: "json"
});

request.done(myData );

request.fail(function( jqXHR, textStatus ) {
alert("Line 279 - Bad request, see firebug");

});

function myData(address) {
     var addFlag="";

     if (address) {
         if (address.Home_Address) {
             addFlag="hm";
             mapAddress=addFlag+", "+address.Home_Address+" "+address.Home_City+", "+address.Home_State;
         }
         else if(address.Work_Address) {
             addFlag="wrk";
             mapAddress=addFlag+", "+address.Work_Address+" "+address.Work_City+", "+address.Work_State;
         }


     }

}

}// myAjaxCall

</script>

Replies(4)

kbwood.au

Re: Using Global var to cycle through AJAX doesn't work

7 years ago

ajax calls happen asynchronously (the first A in AJAX), meaning that they don't return immediately. Your code continues to run and sees that mapAddress is still undefined since the ajax call hasn't returned. You must only access mapAddress within the myData callback from the ajax call.

pizzipie

Re: Using Global var to cycle through AJAX doesn't work

7 years ago

Thanks kbwood,

I have come up with some code that gets the job done but seems really awkward to me.

Would you mind looking this code over with an eye as to how to make the code more professional?

Thanks, R

<script type="text/javascript">

function myAjaxCallGeo(phaseFlag) {

var request = $.ajax({   // ======= first ajax call get all the data =========
    url: "getLatLong2.php",
    type: "GET",
    data: {"id":choice, "phase":phaseFlag},
    dataType: "json"
});

request.done(myData );

request.fail(function( jqXHR, textStatus ) {
alert("Line 279 - Bad request, see firebug");
});

function myData(address) { // ========= parse the data for addresses ============

     if (address) {
        mapHmAddress=address.Home_Address+" "+address.Home_City+", "+address.Home_State;
        mapWrkAddress=address.Work_Address+" "+address.Work_City+", "+address.Work_State;
     }

var myName=address.Display_Name;

if(mapHmAddress) { // ======= if there is a home address =================

phaseFlag=2;

    var request = $.ajax({ // ========= 2nd ajax call store lat & lng ===============
    url: "getLatLong2.php",
    type: "GET",
    data: {"id":choice,
        "phase":phaseFlag,
        "name":myName,
        "address":mapHmAddress}, // home address
    dataType: "text"
});

request.done(myTxtData );

request.fail(function( jqXHR, textStatus ) {
alert("Line 307 - Bad request, see firebug");

});
} // mapHmAddress

if(mapWrkAddress) { // ======= if there is a work address =================

phaseFlag=3;

    var request = $.ajax({   // ========= 3rd ajax call store lat & lng ===============
    url: "getLatLong2.php",
    type: "GET",
    data: {"id":choice,
        "phase":phaseFlag,
        "name":myName,
        "address":mapWrkAddress}, // work address
    dataType: "text"
});

request.done(myTxtData );

request.fail(function( jqXHR, textStatus ) {
alert("Line 329 - Bad request, see firebug");

});
} // mapHmAddress

} // myData

function myTxtData(mytext) { //    "Latitude & Longitude Were Stored Satisfactorily."
         alert(mytext);         // OR "Record Exists, Can't Process:"
}

}// myAjaxCall

</script>