Enable & Disable a Div and its elements in Javascript

I am looking for a method to Enable and Disable the div id="dcalc" and Its children.

<div id="dcalc" class="nerkheArz"
 style="left: 50px; top: 150px; width: 380px; height: 370px;
 background: #CDF; text-align: center" >
 <div class="nerkh-Arz"></div>
 <div id="calc"> </div>
</div>

I want to Disable them at loading the page and then by a click i can enable them ?

This is what i have tried

document.getElementById("dcalc").disabled = true;

You should be able to set these via the attr() or prop() functions in jQuery as shown below:

jQuery (< 1.7):

// This will disable just the div
$("#dcacl").attr('disabled','disabled');

or

// This will disable everything contained in the div
$("#dcacl").children().attr("disabled","disabled");

jQuery (>= 1.7):

// This will disable just the div
$("#dcacl").prop('disabled',true);

or

// This will disable everything contained in the div
$("#dcacl").children().prop('disabled',true);

or

//  disable ALL descendants of the DIV
$("#dcacl *").prop('disabled',true);

Javascript:

// 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;
}

If you want to disable all the div's controls, you can try adding a transparent div on the div to disable, you gonna make it unclickable, also use fadeTo to create a disable appearance.

try this.

$('#DisableDiv').fadeTo('slow',.6);
$('#DisableDiv').append('<div style="position: absolute;top:0;left:0;width: 100%;height:100%;z-index:2;opacity:0.4;filter: alpha(opacity = 50)"></div>');

The following selects all descendant elements and disables them:

$("#dcacl").find("*").prop("disabled", true);

But it only really makes sense to disable certain element types: inputs, buttons, etc., so you want a more specific selector:

$("#dcac1").find(":input").prop("disabled",true);
// noting that ":input" gives you the equivalent of
$("#dcac1").find("input,select,textarea,button").prop("disabled",true);

To re-enable you just set "disabled" to false.

>I want to Disable them at loading the page and then by a click i can enable them

OK, so put the above code in a document ready handler, and setup an appropriate click handler:

$(document).ready(function() {
    var $dcac1kids = $("#dcac1").find(":input");
    $dcac1kids.prop("disabled",true);
    
    // not sure what you want to click on to re-enable
    $("selector for whatever you want to click").one("click",function() {
       $dcac1kids.prop("disabled",false);
    }
}

I've cached the results of the selector on the assumption that you're not adding more elements to the div between the page load and the click. And I've attached the click handler with .one() since you haven't specified a requirement to re-disable the elements so presumably the event only needs to be handled once. Of course you can change the .one() to .click() if appropriate.