Another alternative here is to use a class so you can move your code externally, for example:
<asp:Button ID="btnSave" CssClass="btnSave" runat="server" Text="Save" OnClick="btnSave_Click" />
Then your code can look like this:
jQuery(function($) {
$('.btnSave').click(function() {
alert('hello world');
});
});
Which can be in an external .js, so your users download it once, not as part of the page each time. Alternatively, a bit less efficient is to use the attribute ends-with selector, like this:
jQuery(function($) {
$('input[id$=btnSave]').click(function() {
alert('hello world');
});
});
This will select all <input> elements that have an ID ending in btnSave.
