How to make a webpage read-only (disable input) with jQuery.

$("input:button").attr("disabled", true);  // Disables all buttons
$("input:text").attr("disabled", true);
$("input:checkbox").attr("disabled", true);
$('#myCustomElement').attr("disabled", true);

Some extra css to gray out elements can be usefull too.

Very usefull plugin for KnockoutJS

Map that plain JavaScript object into a view model with the appropriate observables!

More info : http://knockoutjs.com/documentation/plugins-mapping.html
Download : https://github.com/SteveSanderson/knockout.mapping/tree/master/build/output

Add option to html dropdownlist with jQuery

$('#dropdownId').append($('<option>', {
                    value: value,
                    text: text ,
                    selected: true
}));

// Not selected option 

$('#dropdownId').append($('<option>', {
                    value: value,
                    text: text                  
}));

Set a html checkbox to indeterminate state

var checkbox = document.getElementById('myCheckbox');
checkbox.indeterminate = true;