title: Unable to call exactlength property in validate.js
body: <p>I am trying to validate my html file using <code>jquery.validate.js</code>. I need to verify the length of <code>mobileno</code> field which should be of 10 characters. Here is my code:</p>
  
  <pre><code>&lt;!-- mobile number goes here. --&gt;
                  &lt;div class="form-group"&gt;
                      &lt;label for="mobileno" class="col-sm-2 control-label"&gt;Mobile No.&lt;/label&gt;
                      &lt;div class="col-sm-8"&gt;
                          &lt;input type="text" class="form-control" id="mobileno" name="mobileno" placeholder="Mobile No (10 digits)" required autofocus&gt;
                      &lt;/div&gt;
                      &lt;span id="mobileno_error"&gt;&lt;/span&gt;
                  &lt;/div&gt; 
  </code></pre>
  
  <p>The js file  corresponding to it is:</p>
  
  <pre><code> $("#register_form").validate({
          // Specify the validation rules
          rules: {
              name: "required",
              email: {
                  required: true,
                  email: true
              },
              mobileno: {
                  required: true,
                  exactlength: 10
              },
              password: {
                required: true,
                minlength: 6
            },
            confirm_password:{
              required: true,
              equalTo: '#password'
          }
      },
  
          // Specify the validation error messages
          messages: {
              name:"Please enter your name.",
              email: {
                  required: 'Email address is required',
                  email: 'Please enter a valid email address',
              },
              mobileno: {
                  required: 'Mobile number is required',
                  exactlength: 'The mobile number should be of 10 characters.',
              },
              password: {
                  required: 'Password is required',
                  minlength: 'The password should be of minimum 6 characters.',
              },
              confirm_password: {
                  required: 'Confirm password is required',
                  equalTo: 'The confirm password should match password.',
              }
  
          },
  </code></pre>
  
  <p>While leaving the <code>mobileno</code> field I am getting issue like:</p>
  
  <blockquote>
    <p>jquery.validate.js:4 Uncaught TypeError: Cannot read property 'call'
    of undefined.  Exception occurred when checking element mobileno,
    check the 'exactlength' method.</p>
  </blockquote>
  
  <p>I don't know what am I doing wrong.</p>