title: How to solve Uncaught TypeError: $(...).datepicker is not a function
body: <pre><code>&lt;head&gt;
  &lt;meta charset="utf-8" /&gt;
  &lt;title&gt;@ViewBag.Title&lt;/title&gt;
  &lt;link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /&gt;
  &lt;script src="@Url.Content("~/Scripts/jquery-1.7.1.min.js")" type="text/javascript"&gt;&lt;/script&gt;
  &lt;link rel="stylesheet" href="//code.jquery.com/ui/1.10.4/themes/smoothness/jquery-ui.css"&gt;
  &lt;script src="//code.jquery.com/jquery-1.9.1.js"&gt;&lt;/script&gt;
  &lt;script src="//code.jquery.com/ui/1.10.4/jquery-ui.js"&gt;&lt;/script&gt;
  &lt;script&gt;
      $(function () { $("#datepicker").datepicker();});
  &lt;/script&gt;
  </code></pre>
  
  <p>
  <strong>This is my Layout.cshtml</strong></p>
  
  <pre><code>@Html.TextBoxFor(m =&gt; m.Date, new { @id = "datepicker", @style = "width:150px;" })
  </code></pre>
  
  <p><strong>Index</strong></p>
  
  <p>But the datepicker cannot be showed and 
  it shows Log:13 Uncaught TypeError: $(...).datepicker is not a function(anonymous function) @ Log:13fire @ jquery-1.9.1.js:1037self.fireWith @ jquery-1.9.1.js:1148jQuery.extend.ready @ jquery-1.9.1.js:433completed @ jquery-1.9.1.js:103 in the console</p>