// This is the DIV you'd like to disable
// Use the CSS selector to pin dow nthe exact DIV
var div = document.querySelector('div');
// Choose either 1, 2 or 3
// (1) Sets the disabled attribute
div.setAttribute('disabled', true);
// (2) Makes the DIV half transparent
// And changes the cursor to a "not allowed" symbol
div.style.opacity = '0.5';
div.style.cursor = 'not-allowed';
// (3) Delete the DIV
div.remove();
// This will disable just the div
document.getElementById("dcalc").disabled = true;
// or
// This will disable all the children of the div
var nodes = document.getElementById("dcalc").getElementsByTagName('*');
for(var i = 0; i < nodes.length; i++){
nodes[i].disabled = true;
}