var width = 720;
var height = 350;
var modal = document.createElement('div');
modal.className  = "modal";
modal.style.width = width;
modal.style.height = height;
modal.style.position = 'absolute';
modal.style.top = (window.innerHeight - parseInt(modal.style.height)) / 2 +'px';
modal.style.left = (window.innerWidth - parseInt(modal.style.width)) / 2 +'px';

var ngroup = modal;
var title = document.createElement('span');
title.innerHTML = "TYPE GROUP NAME"
var input = document.createElement('input');
input.type = "text";
ngroup.appendChild(title);
ngroup.appendChild(input);

var del = modal;
var dtitle = document.createElement('span');
dtitle.innerHTML = "DO YO WANT TO DELETE SELECTED COLOR(S)"
var dinput = document.createElement('input');
dinput.type = "button";
dinput.value = "yes";
var dinput1 = document.createElement('input');
dinput1.type = "button";
dinput1.value = "no";
del.appendChild(dtitle);
del.appendChild(dinput);
del.appendChild(dinput1);
function openModal(type) {
  var body = document.getElementsByTagName('body')[0];
  body.appendChild(type);
}
function closeModal() {
  document.body.removeChild(modal);
}

document.addEventListener('keydown', function(event) {
    if(event.keyCode == 71) {
        openModal(del);
    }
    else if(event.keyCode == 39) {
        closeModal();
    }
});

<div id="d_dialog" style="display:none" class="dialog">
    <span>DO YO WANT TO DELETE SELECTED COLOR(S)</span>
    <input type="button" value="yes"/>
    <input type="button" value="no"/>
</div>

document.getElementById('d_dialog').style.display = '';

var del = modal;

del.appendChild(dtitle);

modal.appendChild(dtitle);

opendDialog(del);

openDialog(modal);

function createModal()
{
    var width = 720;
    var height = 350;
    var modal = document.createElement('div');
    modal.className  = "modal";
    modal.style.width = width;
    modal.style.height = height;
    modal.style.position = 'absolute';
    modal.style.top = (window.innerHeight - parseInt(modal.style.height)) / 2 +'px';
    modal.style.left = (window.innerWidth - parseInt(modal.style.width)) / 2 +'px';
    return modal;
}

var del = modal;

var del = createModal();