jQuery UI ” $(“#datepicker”).datepicker is not a function”

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jQuery UI ” $(“#datepicker”).datepicker is not a function” – Even if we have a good project plan and a logical concept, we will spend the majority of our time correcting errors abaout asp.net and javascript. Furthermore, our application can run without obvious errors with JavaScript, we must use various ways to ensure that everything is operating properly. In general, there are two types of errors that you’ll encounter while doing something wrong in code: Syntax Errors and Logic Errors. To make bug fixing easier, every JavaScript error is captured with a full stack trace and the specific line of source code marked. To assist you in resolving the JavaScript error, look at the discuss below to fix problem about jQuery UI ” $(“#datepicker”).datepicker is not a function”.

Problem :

When i use DatePicker, jQuery’s UI plugin, in an existing .aspx page I get errors that:

$("#datepicker").datepicker is not a function

However, when I copy and paste the same code that creates and uses the datePicker to an HTML file that’s also in the same directory as the aspx page, it works flawlessly. This leads me to assume that there are some JS files in the aspx page that’s preventing the datePicker or maybe jQuery’s UI JS files to load properly.

Can anyone confirm my beliefs or provide any tips on finding the culprit that’s interfering with jQuery’s UI plugins?

Solution :

I struggled with a similar problem for hours. It then turned out that jQuery was included twice, once by the program that I was adding a jQuery function to and once by our in-house debugger.

If there is another library that is using the $ variable, you can do this:

var $j = jQuery.noConflict();

Also make sure your javascript includes are in the correct order so the jquery core library is defined before the jquery.ui. I’ve had that cause issues.

jQuery “ $(”#datepicker“).datepicker is not a function”

I have fixed the issue by placing the below three files in the body section of the form at the end.

  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.min.js" type="text/javascript"></script>
    <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js" type="text/javascript"></script>
    <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="Stylesheet" type="text/css" />

This error usually appears when you’re missing a file from the jQuery UI set.

Double-check that you have all the files, the jQuery UI files as well as the CSS and images, and that they’re in the correctly linked file/directory location on your server.

If you think that there is a conflict you can use jQuery.noConflict() in your code. Details are in the docs.


If you don’t like typing the full
“jQuery” all the time, there are some
alternative shortcuts:

Reassign jQuery to another shortcut
var $j = jQuery; (This might be the
best approach if you wish to use
different libraries) Use the following
technique, which allows you to use $
inside of a block of code without
permanently overwriting $:

(function($) { /* some code that uses $ */ })(jQuery)

Note: If you use this
technique, you will not be able to use
Prototype methods inside this capsuled
function that expect $ to be
Prototype’s $, so you’re making a
choice to use only jQuery in that
block. Use the argument to the DOM
ready event:

jQuery(function($) { /*some code that uses $ */ });

Again, inside that block you can’t use
Prototype methods

Thats from the end of the docs and might be useful to you

Go for the obvious first: Are you referencing well the jquery-ui.js file?

Try using the network tab of firebug to find if it is loaded, or the InformationView javascript code of the Web Developer Toolbar.

Have you tried using Firebug to 1) determine that there are no Javascript errors and 2) that the #datepicker element exists on the page?

Most likely there is an error prior to the datepicker call that is preventing the datepicker call from executing.

I know that this post is quite old, but for reference I fixed this issue by updating the version of datepicker

It is worth trying that too to avoid hours of debugging.


I just had this issue, and moving the JS references and code towards the bottom of the page before the </body> tag fixed it for me.

Also check the permissions for the directory you download the files into. For some reason when I downloaded this, by default it was saved in a folder with no access allowed! It took forever to figure out that was the problem, but I just had to change the permission for the directory and it’s contents – setting it so EVERYONE = READ ONLY. Works great now.

For me it was just necessary to remove the “defer” property from the declaration of my script

I just ran into a similar issue. When I changed my script reference from self-closing tags (ie, <script src=".." />) to empty nodes (ie, <script src=".."></script>) my errors went away and I could suddenly reference the jQuery UI functions.

At the time, I didn’t realize this was just a brain-fart of me not closing it properly to begin with. (I’m posting this simply on the chance that anyone else coming across the thread is having a similar issue.)

Some file no load before you call.

For example:
Your code:

<%= javascript_include_tag "distpicker.min" %>
<%= javascript_include_tag "distpicker.data.min" %>

Change to this:

<%= javascript_include_tag "distpicker.data.min" %>
<%= javascript_include_tag "distpicker.min" %>

I could fix this problem removing the jquery bundle on the _Layout.cshtml


    <script src="~/Scripts/jquery-1.10.2.js"></script>
    <script src="~/Scripts/kendo/2015.2.902/kendo.all.min.js"></script>


    @RenderSection("scripts", required: false)

Change footer to

    @RenderSection("scripts", required: false)

Have you tried using
$(“#<%= txtDateElementId.ClientID %>”).datepicker();
instead of
when selecting an element by ID using JQuery.

Old question – newer version of .NET (4.5.6) – same issue – new answer

Using NuGet

Make sure you have the following installed via NuGet:

  • jQuery
  • AspNet.ScriptManager.jQuery
  • jQuery.UI.Combined
  • AspNet.ScriptManager.jQuery.UI.Combined

Install them from here [ Tools > NuGet Package Manager > Manage NuGet Packages for Solution ]

Then, jquery and jquery.ui.combined should be added to your ScriptManager in Site.Master. Will look something like this:

    <asp:ScriptManager runat="server">
            <%--To learn more about bundling scripts in ScriptManager see https://go.microsoft.com/fwlink/?LinkID=301884 --%>
            <%--Framework Scripts--%>
            <asp:ScriptReference Name="MsAjaxBundle" />
            <asp:ScriptReference Name="jquery" />
            <asp:ScriptReference Name="jquery.ui.combined" />
            <asp:ScriptReference Name="bootstrap" />
            <asp:ScriptReference Name="WebForms.js" Assembly="System.Web" Path="~/Scripts/WebForms/WebForms.js" />
            <asp:ScriptReference Name="WebUIValidation.js" Assembly="System.Web" Path="~/Scripts/WebForms/WebUIValidation.js" />
            <asp:ScriptReference Name="MenuStandards.js" Assembly="System.Web" Path="~/Scripts/WebForms/MenuStandards.js" />
            <asp:ScriptReference Name="GridView.js" Assembly="System.Web" Path="~/Scripts/WebForms/GridView.js" />
            <asp:ScriptReference Name="DetailsView.js" Assembly="System.Web" Path="~/Scripts/WebForms/DetailsView.js" />
            <asp:ScriptReference Name="TreeView.js" Assembly="System.Web" Path="~/Scripts/WebForms/TreeView.js" />
            <asp:ScriptReference Name="WebParts.js" Assembly="System.Web" Path="~/Scripts/WebForms/WebParts.js" />
            <asp:ScriptReference Name="Focus.js" Assembly="System.Web" Path="~/Scripts/WebForms/Focus.js" />
            <asp:ScriptReference Name="WebFormsBundle" />
            <%--Site Scripts--%>

This solved my same issue.
Thank you.

(”#datepicker“).datepicker is not a function

I also ran into this problem a few days ago. It occurs probably because of having the jquery link more than once in the file. Try searching the whole file for that duplicate content.

It will look somewhat like this:

<script src="https://code.jquery.com/jquery-1.12.1.js"></script>

Keep one in the <head></head> tag and remove all the rest. This will fix the issue.

For those using Laravel, the default app.js has a defer in its declaration.

enter image description here

referencing jQuery twice might cuase the issue.

Your code needs to include JQuery UI, paste this after your jQuery script:

<link rel="stylesheet" href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/themes/smoothness/jquery-ui.css">
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.12.1/jquery-ui.min.js"></script>

If you want higher security then you can download version 1.13 on your PC, as 1.12 has some vulnerabities and Google doesn’t host the newest version yet.

For me the error was happening because of invalid date format:

Invalid code:

        format : 'dd/MM/yyyy'

Valid code:

        format : 'dd/mm/yyyy'

Notice the MM. Please see if the format of your date is correct.
Hope it helps!

In my case, it was solved by changing the import order of the following scripts:
Before (Not work):

After (Working):

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