returning a value

[viviosoft]

Hi guys!

 

Passing values within a function or outside a function has always been a problem for me (to understand).  Here's what I need help with. I have the following function that should return a value.  Just as an fyi... I'm creating a jQuery mobile application (not that it matters for this problem).

 

So I would like to use the value that is returned in another function but can't seem to get at it.  If I alert the value inside the for loop it's fine and I get a value.  So I know the value does exist.

 

So somewhere else on the page I'm calling alert(getSaleman());  ... the alert returns undefined?  Thanks for any help you can provide me.

 

function getSalesman() {
    var sId;
    var salesman;

    sId = urlParam('sId', window.location.href);

    AVDB.readTransaction(function (tx) {
        tx.executeSql("SELECT * FROM stores WHERE id = ?;", [ sId ],
            function (tx, results) {
                for (var i = 0; i < results.rows.length; i++) {
                    var row = results.rows.item(i);
                    salesman = row.sSalesman
                } // for i

            })
    });

    return salesman;

}

[viviosoft]

Well - I guess I should have done a bit more research.  It turns out that you have return values on an asynchronous functions.  You have to create a callback function.  I've done that and this is what I've come up with which works.  If there's a better approach please, by all means, reply.

 

The new callback function:

function getSaleman(callback) {
    var sId;
    sId = urlParam('sId', window.location.href);
    
    var salesmanID = AVDB.readTransaction(function (tx) {
        tx.executeSql('SELECT * FROM stores WHERE id = ? ', [sId], function (tx, results) {
            var len = results.rows.length;
            if(len > 0) {
                var row = results.rows.item(0);
                var temp = row.sSalesman;
                 callback(salesmanID);
            }
        });
    });
}

 

How to call this function and return it's value:

 

        getSaleman(function(value){
            alert(value);
        });