oz. oz. - 5 months ago 56
jQuery Question

Set the selected index of a Dropdown using jQuery

How do I set the index of a dropdown in jQuery if the way I'm finding the control is as follows:

$("*[id$='" + originalId + "']")


I do it this way because I'm creating controls dynamically and since the ids are changed when using Web Forms, I found this as a work around to find me some controls. But once I have the jQuery object, I do not know how to set the selected index to 0 (zero).

Answer

First of all - that selector is pretty slow. It will scan every DOM element looking for the ids. It will be less of a performance hit if you can assign a class to the element.

$(".myselect")

To answer your question though, there are a few ways to change the select elements value in jQuery

// sets selected index of a select box to the option with the value "0"
$("select#elem").val('0'); 

// sets selected index of a select box to the option with the value ""
$("select#elem").val(''); 

// sets selected index to first item using the DOM
$("select#elem")[0].selectedIndex = 0;

// sets selected index to first item using jQuery (can work on multiple elements)
$("select#elem").prop('selectedIndex', 0);