title: input value attribute renders twice
body: <p>This is a rather interesting issue that was quite hard to spot...and I cannot resolve it. In a nutshell, I have the following in a view trying to render a date field (ignore archiac syntax - it's an old project);</p>
  
  <pre><code>        &lt;%: Html.TextBoxFor(model =&gt; model.DateOfRenewal, 
                  new { 
                      type = "date",
                      placeholder = "DD/MM/YYYY",
                      Value = (Model.DateOfRenewal != null) ? Model.DateOfRenewal.Value.ToString("yyyy-MM-dd") : "" 
                  })%&gt;
  </code></pre>
  
  <p>Now on the model, the date format attribute is set to "dd/MM/yyyy" appropriately. We're rendering to "yyyy-MM-dd" when generating the HTML in order for a jquery library (webshim polyfiller) to pick up the date correctly when it starts running against the field. I don't have control over this library so I'm stuck with it and I have control only over the MVC side of things.</p>
  
  <p>What's happening is that the field above looks ok when you inspect it but viewing the source shows the following;</p>
  
  <pre><code>&lt;input Value="2008-05-12" data-val="true" data-val-date="The field Renewal Date must be a date." 
         id="Ratings_DateOfRenewal" 
         name="Ratings.DateOfRenewal" placeholder="DD/MM/YYYY" 
         type="date" 
         value="12/05/2008 00:00:00" /&gt;
  </code></pre>
  
  <p>Notice that <code>Value</code> and <code>value</code> are both present. The lower case version is what goes in there as part of <code>TextBoxFor</code> and the uppercase <code>Value</code> is what appears in my custom attribute when specifying in the view. </p>
  
  <p>However, changing the custom attribute in the view from an uppercase to a lower case is runs fine but it does <em>not</em> have the custom date format. As a result, I get a blank field as webshim cannot interpret it.</p>
  
  <p>Is there anyway to get a custom date format without;</p>
  
  <ul>
  <li>Changing the model attribute (required for server side validation)</li>
  <li>Changing/modifying the jquery library</li>
  </ul>
  
  <p>In a nutshell, is there a way to get the custom formatted date as a single, lowercase <code>value</code> html attribute when rendered?</p>
  
  <p><strong>EDIT</strong>
  The marked answer below changes the lowercase <code>value</code> to the specified format. To fulfill the original request, the MVC markup has to change to a lowercase <code>value</code> as well. This fixes the issue.</p>
  
  <p><strong>EDIT2</strong>
  The duplicate mark is invalid. While the situation is very close, none of the answers in the linked post work in this situation - inherently marking it as different.</p>