Function Not Returning Value To Other Function

Tried to write a function which reads data from a text file. The function is working fine but I want to read its data in other function. Could some one help me telling how to retur

Solution 1:

In your code you are using AJAX trough JQuery:

$.get(url, callback) 

The $get method hits the url and passes the result to the callback method, it does not return it. The callback does not get invoked immediately, due to AJAX being asynchronous, instead something like this happens:

1. $.get is called
2. the read method continues (exits in your case, as there is no other code)
3. the $.get receives a response from the server
4. the callback function gets called, if the server succeeded with getting the data

In the above sequence, the second step may be swapped with any of the steps after it. Still, this sequence is to show that there is no relationship between when the read method exits and when the processing of the data occurs. So, if you need to do something with the result (show it on the page) then you should do this inside the callback method.

Here is an edited example with your code:

functionread() {

    $.get("version.txt?_ts=" + newDate().getTime(), function(data) {

        var y1 = parseInt(data[0]);
        var y2 = parseInt(data[1]);
        var y = (y1*10)+y2;

        document.write(y);
    });
}

---

In addition to the asynchronous nature of AJAX, there is another problem with your code. In your read method, you expect to return a value, but actually it does not return anything. This renders the drr function to be invalid.

Solution 2:

do like this:

functionread()
    {

    $.get("version.txt?_ts=" + newDate().getTime(), function(data) {


    var y1= parseInt(data[0]);
    var y2= parseInt(data[1]);
    var y=  (y1*10)+y2;

     document.write(y); /* this is the change, process the result when it's received here */

      });

    }

functiondrr()
    {
     read();
    }

also change html to a more proper syntax

<bodyunload="read();">

---

generally, when you have $.ajax() call, it is asynchronous - request is made and the success handler is executed, when request is processed successfully.

so if you use return value of the ajax() call, it's not the response received from the server, but rather a request object.

Solution 3:

$.get is async function, there's no return for read function, you need use callback:

functionread(callback) {

    $.get("version.txt?_ts=" + newDate().getTime(), function(data) {

        var y1 = parseInt(data[0]);
        var y2 = parseInt(data[1]);
        var y = (y1 * 10) + y2;

        callback(y);
    });

}

functiondrr() {

    read(function(txt) {

        document.write(txt);
    });

}

Solution 4:

Try this.

functionread() {
            var result=0;
                $.get("version.txt?_ts=" + newDate().getTime(), function (data) {
                    var y1 = parseInt(data[0]);
                    var y2 = parseInt(data[1]);
                    var y = (y1 * 10) + y2;
                    result=y;
                });
             return result;
            }

            functiondrr() {
                var d = read();
                document.write(d);
            }