This code is a combination of JavaScript and jQuery that...

August 25, 2025 at 10:54 PM

$('#AssignedCM').on('change', function () {

    let selectedId = this.value;

    if (selectedId != "") {

        updateWorkerInfoByUnitID(selectedId, function (phone, cell, sId) {
            $('#CMPhone').val(phone);
            $("#CMMail").attr("href", "mailto:" + sId + "@@dot.ca.gov").removeAttr("disabled");
        });

    }
    else {
        $('#CMPhone').val("");
        $("#CMMail").attr({ "href": "#", "disabled": "disabled" });
    }

});

 function updateWorkerInfoByUnitID(id, callback) {
     $.ajax({
         url: '?handler=WorkerInfoByUnitId&id=' + id, // Ensure it matches the C# handler
         type: 'GET', // Use GET instead of POST
         dataType: 'json',
         success: function (response) {
             if (response.success) {
                 let phone = response.phone;
                 let cell = response.cell;
                 let sId = response.sId;

                 // Call the callback function with the retrieved values
                 callback(phone, cell, sId);
             }
         }
     });
 }

This code is a combination of JavaScript and jQuery that handles the behavior of updating specific worker information when a dropdown menu selection is changed. Here's a detailed breakdown of what the code does:

1. Event Listener: `$('#AssignedCM').on('change', ...)`

The $('#AssignedCM').on('change', ...) part is an event listener for the change event on an HTML element (likely a dropdown menu or <select> element) with the ID AssignedCM.
It executes the provided function whenever the value of the dropdown changes.

2. Retrieve Selected Value

Inside the event handler, the selected value of the dropdown is retrieved using this.value and stored in a variable selectedId.

3. Conditional Check

If selectedId is not an empty string (selectedId != ""), the code assumes a valid selection has been made.
Otherwise, it resets the target elements (explained in Step 5).

4. Data Fetching

If a valid selection (selectedId) exists, the function updateWorkerInfoByUnitID is called with:
- selectedId as the parameter to specify the worker/unit for which data is being fetched.
- A callback function that will handle the data (phone, cell, and sId) once it is returned.

Function: `updateWorkerInfoByUnitID(id, callback)`

This function makes an AJAX GET request to retrieve worker information from a server-side endpoint.
- The request's URL is ?handler=WorkerInfoByUnitId&id=<selectedId>.
- id represents the selected dropdown value.
- The dataType is set to json, so the expected server response is in JSON format.
On a successful AJAX response:
- The success callback checks if response.success is true.
- It retrieves the worker information (phone, cell, and sId) from the response.
- It then passes these values to the callback function provided by the on('change', ...) handler.

Callback in Event Listener

The callback function in the event handler updates the UI dynamically with the retrieved worker information:
- Sets the value of the input field with ID CMPhone to the worker's phone.
- Updates the href attribute of an anchor tag with the ID CMMail to create a mailto: link for the worker's email (constructed using sId).
- Removes the disabled attribute from the CMMail anchor tag.

5. Default Behavior for Empty Selection

If no valid selection is made (i.e., selectedId == ""):
- The value of the CMPhone input field is cleared.
- The CMMail anchor tag is updated:
  - Its href attribute is set to #.
  - It is disabled by setting a disabled attribute.

Summary

This code is used to update a user interface with contact information (phone number and email) of a worker based on the user's selection in a dropdown menu. The information is fetched asynchronously from a server using an AJAX request and dynamically applied to the UI. If no valid selection is made, the contact information fields are cleared and disabled.

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