How to use JQuery with Master Pages?

Question

I can get simple examples to work fine as long as there's no master page involved. All I want to do is click a button and have it say "hello world" with the javascript in a .js file, using a master page. Any help very much appreciated :)

Firth

Answer 1

EDIT

As @Adam points out in the comments, there is a native jQuery mechanism that basically does the same thing as the hack in my original answer. Using jQuery you can do

 $('[id$=myButton]').click(function(){ alert('button clicked'); }); 

My hack was originally developed as a Prototype work around for ASP.NET and I adapted it for the original answer. Note that jQuery basically does the same thing under the hood. I recommend using the jQuery way, though, over implementing my hack.

Original answer left for comment context

When you use a master page, ASP.NET mangles the names of the controls on the dependent pages. You'll need to figure out a way to find the right control to add the handler to (assuming you're adding the handler with javascript).

I use this function to do that:

function asp$( id, tagName ) {
    var idRegexp = new RegExp( id + '$', 'i' );
    var tags = new Array();
    if (tagName) {
        tags = document.getElementsByTagName( tagName );
    }
    else {
        tags = document.getElementsByName( id );
    }
    var control = null;
    for (var i = 0; i < tags.length; ++i) {
       var ctl = tags[i];
       if (idRegexp.test(ctl.id)) {
          control = ctl;
          break;
       }
    }

    if (control) {
        return $(control.id);
    }
    else {
        return null;
    }
}

Then you can do something like:

jQuery(asp$('myButton','input')).click ( function() { alert('button clicked'); } );

where you have the following on your child page

<asp:Button ID="myButton" runat="server" Text="Click Me" />

Africanize

I'm pretty new at this and had no idea about the name-mangling. I'll give this a go later. I appreciate it. – Firth

Get used to using the 'View source' (Or equivalent) on your browser. This allows you not only to check that your pages are rendering the ay that you want them to, but to learn tricks from othe people's pages. – Insurable

is that a deliberate typo '$asp' v 'asp$'? i couldnt get this to work - it picks up the control ok but jQuery call doesn't work for some reason – Fiber

You are WAY over-engineering this. You can replace this whole function with $('[id$=myButton]').click(function(){ alert('button clicked'); }); – Apparition

Actually, this was before I used jQuery much at all and the hack was a Prototype replacement with usage adapted for jQuery. I've moved on to ASP.NET MVC and thankfully don't have to worry about name mangling at all. – Africanize

Using the ClientID to get the control name is a much simpler method and will always work because no matter what the master/content page creates as a ID, the javascript in the content page will correctly hard code in on generation. Though it wouldn't work on any included javascript files. :( – Leatherman

That makes sense. I just wanted to say something so people know this isn't even close to best practice. – Apparition

@achinda99: Simpler? I beg to differ; it forces you to tightly-couple server-side code with frontend javascript and markup. If the id of the elements in question are likely to change, you can give it a css class and select it that way. – Apparition

@Adam - your way is the easiest. #1275306 – Henchman

Answer 2

If your site has content pages in other folders, using the Page's ResolveUrl method in the src path will ensure that your js file can always be found:

<script type="text/javascript" src='<%= ResolveUrl("~/Scripts/jquery-1.2.6.min.js") %>' ></script>

Atoll

When i put this is header tag and run, the page error and provide this The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>). Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Web.HttpException: The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>). – Meshach

Pasted from @Jos suggestion: As an answer to @Sarawut's comment, you get his problem for instance when you use themes. The themes will try to add controls to the head, but this will fail when there are <%...%> tags in the head already. To prevent this, you can add the script through code (in the master page): Public Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Dim lit As New Literal() lit.Text = String.Format("<script type='text/javascript' src='{0}'><" & "/script>", ResolveUrl("~/Script/jquery-1.6.1.js")) Page.Header.Controls.Add(lit) End Sub – Wilburn

I had to switch back to using asp.net webforms and your answer resolved my problem as I couldn't use the mvc 3 razor syntax of @Url.Content ... e.g. <script src="@Url.Content("~/Scripts/modernizr-1.7.min.js")" type="text/javascript"></script> Thanks! – Digitalize

Answer 3

Make sure that jQuery is being added in the master page. Given that you have this control:

<asp:Button ID="myButton" runat="server" Text="Submit" />

You can wireup the javascript with this:

$(document).ready(function() {
    $('[id$=myButton]').click(function() { alert('button clicked'); });
});

$(document).ready() fires when the DOM is fully loaded, and all the elements should be there. You can simplify this further with

$(function() {});

The selector syntax $('[id$=myButton]') searches elements based on their id attribute, but matches only the end of the string. Conversely, '[id^=myButton]' would match the beginning, but for the purposes of filtering out the UniqueID that wouldn't be very useful. There are many many more useful selectors you can use with jQuery. Learn them all, and a lot of your work will be done for you.

The problem is that ASP.Net creates a unique id and name attribute for each element, which makes finding them difficult. It used to be that you'd need to pass the UniqueID property to the javascript from the server, but jQuery makes that unneccessary.

With the power of jQuery's selectors, you can decouple the javascript from the server-side altogether, and wireup events directly in your javascript code. You shouldn't have to add javascript into the markup anymore, which helps readability and makes refactoring much easier.

Apparition

Answer 4

Just move the <script type="text/javascript" src="jquery.js" /> tag into the head tag in the master page. Then you can use jquery in all content pages.

There is no magic about using master pages with jQuery.

Freehanded

Answer 5

Adam's solution is the best. Simple!

Master page:

<head runat="server">    
    <title></title>
    <link href="~/Styles/Site.css" rel="stylesheet" type="text/css" />
    <script src="Scripts/jquery-1.3.2.js" type="text/javascript"></script>
    <asp:ContentPlaceHolder ID="HeadContent" runat="server">
    </asp:ContentPlaceHolder>    
</head>

Content page:

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">       
<script type="text/javascript">
    $(document).ready(function () {
        $("[id$=AlertButton]").click(function () {
            alert("Welcome jQuery !");
        });
    }); 
</script> 
</asp:Content>

where the button is

<asp:Button ID="AlertButton" runat="server" Text="Button" />

Brantbrantford

Answer 6

Reference the the Jquery .js file in the head of the MasterPage as follows:

<script type="text/javascript" src="/Scripts/jquery-1.2.6.min.js"></script> 

(some browsers don't like ending it with />)

Then you can write things like

$('#<%= myBtn.ClientID%>').show() 

in your javascript making sure to use the ClientId when referencing an ASP.Net control in your client code. That will handle any "mangling" of names and ids of the controls.

Kazukokb

Should I have expected this to work? $('#<%= Button1.ClientID%>').click(function() { alert('Hello world!'); }); This code is in my .js file. I know I have everything set up correctly because if I copy the 'mangled' id from the page source it works fine. – Firth

The <% %> syntax only works within the .aspx file. So if you want to use that, you need to put your script in a <script> block within your aspx file. – Eldrid

Answer 7

Master page:

The jQuery library goes in the master page. See if the path is correctly referenced. You might like to add the extra documentation like this:

<head>
    <script type="text/javascript" src="/Scripts/jquery-1.2.6.min.js"></script> 
    <% if (false) { %>
    <script type="text/javascript" src="/Scripts/jquery-1.2.6-vsdoc.js"></script>
    <% } %>
</head>

Master page:

<head>
<script type="text/javascript">
    $(document).ready(
        function()
        {
            alert('Hello!');
        }
    );
</script>
</head>

CodeBehind for content pages and user controls:

this.textBox.Attributes.Add("onChange",
    String.Format("passElementReferenceToJavascript({0})", this.textBox.ClientID));

Stefansson

Answer 8

Check out this post:

http://blogs.msdn.com/webdevtools/archive/2008/10/28/rich-intellisense-for-jquery.aspx

also explains how to get intellisense for jQuery in Visual studio.

Commit

Answer 9

In case if some one wants to access a label, here is the syntax

$('[id$=lbl]').text('Hello');

where lbl is the label id and the text to display in the label is 'Hello'

Trass

Answer 10

When pages are rendered along with master pages, control id gets changed on page rendering so we can't refer them in jQuery like this #controlid. Instead we should try using input[id$=controlid]. If control is rendered as input control or if as anchor tag use a[id$=controlid] in jQuery.

Potshot

Answer 11

I also started with the simplest of examples and had no luck. I finally had to add the jquery .js file outside of the <head> section of the master page. It was the only way I could get anything to work in Firefox (haven't tried other browsers just yet).

I also had to reference the .js file with an absolute address. Not entirely sure what's up with that one.

Thimbleweed

Answer 12

Adam Lassek linked to using jQuery selectors, though I think its worth explicitly calling out selecting elements by their class, as opposed to their id.

e.g. Instead of $("#myButton").click(function() { alert('button clicked'); });

instead use $(".myButtonCssClass").click(function() { alert('button clicked'); });

and add the class to the button:

<asp:Button ID="myButton" runat="server" Text="Submit" CssClass="myButtonCssClass" />

This has the benefit of not having to worry about whether two control ids 'end' the same way in addition to being able to apply the same jQuery code to multiple controls at a time (with the same css class).

Carry

Answer 13

• PROBLEM --> when using Site.Master pages the control id names (for ASP controls) get the ContentPlaceHolderID prefixed to them. (Note this not a problem for non-asp controls as they don't get 'reinterpreted' - i.e. they just appear as written)

• SOLUTIONS:

  • 1. Simplest --> add ClientIDMode="Static" to the asp control definition (or set with properties) in aspx page
  • Alternatives include:
  • 2. Hardcoding the ContentPlaceHolderID name in the js code e.g "#ContentPlaceHolder1_controlName" - eek!!!!
  • 3. using the <%= controlName.ClientID %> in the ASP page - plus, assigning it - there- to a variable (or object of variables). The variable (or object dot notation) can then be used in external js page (NOTE: Can't use <%= controlName.ClientID %> in external js)
  • 4. Using CssClass with a unique(same name as ID) in ASP page and refering to the control as ".controlName" instead of "#controlName"
  • 5. Using the "[id$=_controlName]" instead of "#controlName" - this is involves a small search and is looking for a control that ends with the unique name - that way the start is irrelevant

Initiate