Where am I going wrong in my attempts to use a callback function?

Question

Where am I going wrong in my attempts to use a callback function?

I am currently attempting to implement a callback function for this particular JavaScript function.

function Filtering_GetSite(siteElement) {

$.ajax({

    type: "POST",
    url: "samle.asmx/f1",
    data: "",
    contentType: "application/json; charset=utf-8",
    dataType: "json",

    success: function (response) {

        var filtersitedetails = response.d;
        var appendItem = "";

        $(siteElement).empty();

        $.each(filtersitedetails, function (index, Filtering_GetSiteInfo) {

            var activeappend = "";
            var id = Filtering_GetSiteInfo.id;
            var site = Filtering_GetSiteInfo.site;

            activeappend = "<option value=" + id + ">" + site + "</option>";

            appendItem += activeappend;

        });

        $(siteElement).prepend('<option disabled="disabled" selected="selected" value="">Select Site</option>');
        $(siteElement).append(appendItem);

    },

    error: function (response) {
        alert("error in Filtering_GetSite");
    }
});
}

This is the method I am using to call the function and trying to incorporate a callback:

Filtering_GetSite("#txt-site-name", function () {
           alert('ok')
           Dashboard_GetAgentInfo(agentParam,agentElement);
       });

However, I am facing an issue where the alert does not trigger upon completion of the function. How can I resolve this?

javascript

Answer 1

Answer №1

The reason for the issue you are experiencing is likely due to the fact that the method ajax is not being passed and executed correctly.

To resolve this, modify the method signature of Filtering_GetSite so that it includes a second parameter, which will be used as the callback. Then, upon successful execution of the ajax, simply invoke the callback function.

function Filtering_GetSite(siteElement, callback) {
   ...

   success: function() {
      ....

      callback();
   }

  ...
}

Answer 2

The reason for the issue you are experiencing is likely due to the fact that the method ajax is not being passed and executed correctly.

To resolve this, modify the method signature of Filtering_GetSite so that it includes a second parameter, which will be used as the callback. Then, upon successful execution of the ajax, simply invoke the callback function.

function Filtering_GetSite(siteElement, callback) {
   ...

   success: function() {
      ....

      callback();
   }

  ...
}

Answer 3

Answer №2

Make sure to include the callback parameter in your Filtering_GetWeb method. Here's an example:

function Filtering_GetWeb(webElement, callback) {
}

To trigger the callback, use callback() within the desired location. For instance, inside the completed section;

Answer 4

Make sure to include the callback parameter in your Filtering_GetWeb method. Here's an example:

function Filtering_GetWeb(webElement, callback) {
}

To trigger the callback, use callback() within the desired location. For instance, inside the completed section;

Answer 5

Answer №3

It's a wrap!

Make sure to include a second parameter for the callback function.

I have also included a condition so that if you forget the second parameter, it will check whether the callback is a function or not. This way, you can simply call the function as Filtering_GetSite(sample) instead of

Filtering_GetSite(sample,function(){})

function Filtering_GetSite(siteElement, callback) {
     if (typeof (callBack) == "function") {
            callBack();
        }
}

Answer 6

It's a wrap!

Make sure to include a second parameter for the callback function.

I have also included a condition so that if you forget the second parameter, it will check whether the callback is a function or not. This way, you can simply call the function as Filtering_GetSite(sample) instead of

Filtering_GetSite(sample,function(){})

function Filtering_GetSite(siteElement, callback) {
     if (typeof (callBack) == "function") {
            callBack();
        }
}

Where am I going wrong in my attempts to use a callback function?

Answer №1

Answer №2

Answer №3

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