Getting ID for a list item with JS

Question

I am trying to set up a simple subscription tool where users can subscribe to or unsubscribe from various distribution list. The idea is that you select a user through a people picker ('subuser'), select a list ('sublist') and click either subscribe (so you are added to the selected list) or unsubscribe (so you are deleted from the selected list). I have succeeded with the subscribe part, but got stuck at unsubscribe. I know how to delete an item from a list, but to do that I need to have an item's ID (or is there any other way?). This is the part of my code that I want to use to get the ID for the item that includes a user selected via the people picker, but itemID is undefined:

function removeUser()     
{    
var clientContext = new SP.ClientContext(siteurl);    
var value1 = document.getElementById('subuser').value;    
var value2 = document.querySelector('input[name="sublist"]:checked').value;    
var queryLookup = "<Where><Eq><FieldRef Name='UserName' LookupId='TRUE' /><Value Type='Lookup'>"+ value1 +"</Value></Eq></Where>";
var itemID="";

$().SPServices({    
    operation: "GetListItems",    
    async: false,    
    listName: value2,    
    CAMLViewFields: "<ViewFields><FieldRef Name='ID'/></ViewFields>",    
    CAMLQuery: queryLookup,    
    completefunc: function(xData,Status) {    
        itemID = $(xData.responseXML.xml).find("z\\:row").attr("ows_ID");
        }
    });
}

SPServices can be replaced by any other working solution. Thank you for any suggestions.

Answer 1

Here is the sample code using that we can get last item ID using REST API coding :

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script> 
<script type="text/javascript">
    function getListData() { 
        $.ajax({ 
            url: _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getByTitle('ListA')/items?$select=ID,Title",
            type: "GET",
            headers: { "accept": "application/json;odata=verbose", "content-type": "application/json;odata=verbose", },
            success: onQuerySucceeded, error: onQueryFailed
        });
    }
    function onQuerySucceeded(data) {
        console.log(data.d.results);
        $("#newsitems").append('<table>');
        $("#newsitems").append('<tr><td style="font-weight:bold">ID </td><td style="font-weight:bold">Title </td></tr>');
        $.each(data.d.results, function (key, value) {
        $("#newsitems").append('<tr>'); 
        $("#newsitems").append('<td>'+value.ID+ '</td>'); 
        $("#newsitems").append('<td>'+value.Title+ '</td>');                                    
        $("#newsitems").append('</tr>')                  });
        $("#newsitems").append('</table>');
    }
    function onQueryFailed() {
        alert('Sorry An Error Has Occurred!');
    }
    ExecuteOrDelayUntilScriptLoaded(getListData, "sp.js")
</script>​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
<div id="newsitems"></div>

Reference URL :

https://social.msdn.microsoft.com/Forums/office/en-US/e9964e5a-5496-44ba-a969-f239df1b2651/sharepoint-and-rest-api-trying-to-display-list-item-id?forum=sharepointdevelopment