$("Selector").on("change",function(e){
    if(e.ctrlKey){
        console.log("ctrl is pressed");
    }
    else{
        console.log("ctrl is not pressed");
    }
});

var ctrlKeyHeld = false;

$(document).keydown(function(e) {
    ctrlKeyHeld = e.ctrlKey;
}).keyup(function() {
    ctrlKeyHeld = false;
})

$("#foo").on("change",function(e){
    if (ctrlKeyHeld){
        console.log("ctrl is pressed");
    }
    else{
        console.log("ctrl is not pressed");
    }
});