For all selectors, see w3schools

Single selectors

The element selector: $("p") selects all <p> elements on a page
The #id selector: $("#test") selects the element with id="test"
The .class selector: $(".test") selects all elements with class="test"

Combined selectors

$("#pnlSummary legend") will select the legend elements within the element with id="pnlSummary".

Enabling/disabling controls - effects on HTML

jQuery HTML
.prop("disabled", true) disabled=""
.prop("disabled", false) removes disabled=""
.prop("disabled", "disabled") disabled=""
.attr("disabled", true) disabled="disabled"
.attr("disabled", false) removes disabled="disabled"
.attr("disabled", "disabled") not allowed in jQuery

- Tested on button and fieldset.
- Tested using Firefox Scratchpad with jQuery 1.11.0
- You can check the version of jQuery with: alert(jQuery.fn.jquery);

Controls - specific actions

Textbox, Label (span)

Read: $("txt").val();
Write textbox: $("txt").val("123");
Write label: $("lbl").text("123"); // if the text contains html that needs processing, use .html instead.
Enable: $("txt").prop("disabled", false);
Mind that sometimes also the css will cause the textbox to be disabled. In this case you also need something like this;
Disable: $("txt").prop("disabled", true);
Read only: $("txt").attr("readonly", true);
Not read only: $("txt").attr("readonly", false);

Checkbox (jQuery 1.6+)

Read checkbox: $("#cb").prop("checked");
Returns true or false
Check: $("cbCheck").prop("checked", true);
Uncheck: $("cbCheck").prop("checked", false);
Enable: $("cbCheck").prop("disabled", false);
Remark: in IE you also need to enable the surrounding span:
$("cbCheck").closest("span").prop("disabled", false);
Disable: $("cbCheck").prop("disabled", true);
Check if disabled: $("cbCheck").prop("disabled") - returns true or false
Event: OnClick

Dropdown list

Get the value: $("ddl").val();
Set the value: $("ddl").val(QuoteDTO.Frequency);

Get the selected text: $("ddl option:selected").text();
Get text for a value: $("ddl option[value=" + ID + "]").text()
Update the selected text: $("ddl option:selected").text(text);

Set the selected index: $("ddl")[0].selectedIndex = 0;

Disable: $("ddl").attr("disabled", true);
Empty: $("ddl").empty();
Add a new item: $("ddl").append(new Option(text, value, defaultSelected, selectedNow));


// Dto.Items contains 2 strings per item. The first contains the value, the second the text.
for (var count = 0; count < Dto.Items.length; count += 2) {
  items += '<option value="' + Dto.Items[count] + '">' + Dto.Items[count + 1] + '</option>';

Event: OnChange


Enable: $("#btn").prop("disabled", false);
jQueryUI: $("#btn").button("enable");
Disable: $("#btn").prop("disabled", "disabled");
jQueryUI: $("#btn").button("disable");
Check if disabled: $("#btn").prop("disabled")
Event: OnClientClick="btn_Click(); return false;"
The return false is to avoid the postback.
Change text: $("#btn").val("Save");
The ASP.NET OnClientClick is not rendered into a onclick event if the button is disabled on page load.

Panel (div)

Enable: $("#pnl").removeAttr("disabled");
Remark: Also the controls in a panel will be disabled. So you also need to enable the separate controls in the panel:
$("#pnl :input").removeAttr("disabled");
Check if disabled: $("pnl").prop("disabled")
Hide: $("#pnl").hide();
Remark: this will set the style display to none.
Show: $("#pnl").show();


Enable: $("#rb").attr("disabled", false);
Disable: $("#rb").attr("disabled", true);
$("#rb").prop("checked", true)


Initialize: $("#id").datepicker({ dateFormat: "dd/mm/yy", showWeek: true });

Controls - generic

Change backcolor: $("#").css("background-color", "red");
Change textcolor: $("#").css("color", "red");
Add class:$("txt").addClass("textbox");
Add class:$("txt").removeClass("textbox-ro");

Custom attributes

Read custom attributes

var customAttribute = $("aspnetForm").attr("customAttribute");

Write custom attributs (C#)

JavaScriptSerializer s = new JavaScriptSerializer();
Page.Form.Attributes.Add("Translations", s.Serialize(translations));

Interesting extended controls





JSON examples

Single parameter
var parameters = '{"id":' + $("#txtId").val() + '}'; // {"id": 15}
Multiple parameters
var parameters = '{"id":' + $("#txtId").val() + ', "name":' + $("#txtName").val() + ', "isCustomer":' + JSON.stringify(false) + '}';
Object parameters
var parameters = '{"contact":' + JSON.stringify(ContactDto) + '}';


Common: jQuery for the asp.net developer
Using complex types
Native JSON support (in FireFox, but also in IE,...0

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