不确定这是否适用于您的上下文，但我认为您应该立即显示带有“请稍候”消息的模态，因此代码的外观如下：

function getCallHistory() {
    $('tr').on('contextmenu', 'td', function(e) { //Get td under tr and invoke on contextmenu

        // Show the modal right away with a message
        $("#lli").html('Loading fresh call history, please wait...');
        $("#lli").modal();

        e.preventDefault(); //Prevent defaults'
            var idparm = $(this).attr('id');
            var arparm = idparm.split(":");
            var id     = arparm[1];
                id     = id.replace(/\s+/g, '');
            var call   = $(this).html();
            var call   = call.replace(/\s+/g, ''); // remove spaces
                    //Look for slash or dash (/,-, or any special character)
                    var vals = [call].map((item) => item.split(/\W+/,1));
                    var call = vals[0];

        $.ajax({
            type: "GET",
            url: "getCallHistory.php",  
            data: {call : call, id : id},
            success: function(response) {

                // Overwrite the waiting message
                $("#lli").html(response);  // Writes to the lli DIV at the bottom of index.php

                $("#lli").modal();  // Opens the modal dialog box
            },
            error: function() {
                alert('Last Query Failed, try again.');
            }
        });
    });
}