javascript return value is always undefined

Question

I\'m trying to retrieve the 2 attributes of seprated function and I debug there values before the end of the function and they have a value but the return value is alwas und

Answer 1

Cause you're not returning it from the main function, you're returning it from the embedded anonymous function which isn't doing anything with it. Do this:

function STAAPlanlat(){
var lat;
var lan;
alert ("the function");
if (navigator.geolocation) {
    //we supposed to call the handlers of the expections 
    navigator.geolocation.watchPosition(function(position) {
        alert("show position ");
        //  x.innerHTML="Latitude: " + position.coords.latitude +"<br />Longitude: " + position.coords.longitude;   
        lat=position.coords.latitude;
        lan=position.coords.longitude;  

        //x.innnerHTML=out
        alert(lat+"<"+lan);
    });
    return lan;
}
else
    alert("error");
}

Answer 2

You are returning in the anonymous function and this value is never assigned to anything. You can do what you want with a callback.

// untested code, hope it works
function STAAPlanlat(callback){
    alert ("the function");
    if (navigator.geolocation) {
        navigator.geolocation.watchPosition(function(position) {
            var lat=position.coords.latitude;
            var lan=position.coords.longitude;  
            callback(lat, lan);
        });
    }
    else{
        alert("error");
    }
}

And your test function...

function test(){
    var out;
    STAAPlanlat(function(lat, lon) { out = lat; });
}

Answer 3

because function STAAPlanlat doesn't return any value. your anonymous function returns lan but it is asynchronous callback. add this before return lan;:

document.getElementById("STAAPlanlat").value = "lan is" + lan;