function filterContactByItemID(lookupFieldId) {
    var currentItemID = GetUrlKeyValue("ID"); 
    if(!currentItemID) return; 
    var siteUrl = _spPageContextInfo.webAbsoluteUrl; 
    var contactsListUrl = siteUrl + "/_api/web/lists/getbytitle('Contacts')/items?$filter=AccountID eq '" + currentItemID + "'";

    fetch(contactsListUrl, {
        method: "GET",
        headers: {
            "Accept": "application/json;odata=verbose",
        }
    })
    .then(response => {
        if (!response.ok) {
        throw new Error('Network response was not ok');
        }
        return response.json(); 
    })
    .then(data => {
        var contacts = data.d.results;
        var lookupField = document.getElementById(lookupFieldId);
        var selectedValue = lookupField.value;

        lookupField.innerHTML = "";

        var option = document.createElement("option");
        option.value = 0; 
        option.text = "(none)"; 
        lookupField.appendChild(option);

        contacts.forEach(function(contact) {
            var option = document.createElement("option");
            option.value = contact.ID; 
            option.text = contact.Full_x0020_Name0; 
            lookupField.appendChild(option);
        });

        if (selectedValue != 0) {
            lookupField.value = selectedValue;
        }
    })
    .catch(error => {
        console.error('There has been a problem with your fetch operation:', error);
    });
}