title: Multipart File submit never hit the server method
body: <p>I have an ajax call:
  what happens is that I click on an Image that clicks on "input file" that I don't want it to be shown. when the input val() is changed method <code>uploadListener()</code> is invoked which is basically an ajax method that get the file to the server "upload it to server"
  code  goes like this:
  html:</p>
  
  <pre><code>&lt;img id="${assayAssessRequest.id}" src="[@spring.url '/images/buttons/upload.jpg'/]" onclick="uploadFile(this);" title="Upload File" /&gt;
  &lt;form id="uploadForm" action="[@spring.url '/assay/designability/uploadFile.htm'/]" method="POST" enctype="multipart/form-data"&gt;
          &lt;div style="display: none;"&gt;
          [@spring.formInput path="multiPartBean.file" fieldType="file" attributes="title='path' class='upload' accept='.txt,.csv,.zip'" /]
          [@spring.formHiddenInput path="multiPartBean.fileName" attributes=" onchange='uploadListener();'class='uploadFileName'" /]
          [@spring.bind "multiPartBean"/]
          &lt;/div&gt;
          &lt;input type="submit" id="uploadButton" value="upload" /&gt;
      &lt;/form&gt;
  </code></pre>
  
  <p>javaScript:</p>
  
  <pre><code>function uploadFile(){
      document.getElementById('inputFile').click();
  }
  
  function uploadListener(){
     $('#uploadForm').attr("action","[@spring.url    '/assay/designability/uploadFile.htm'/]");
     alert($('#uploadForm').attr('action'));
     this.document.getElementById("uploadForm").submit = true;
     alert("After Submit");
     return false;
  }
  </code></pre>
  
  <p>server controller:</p>
  
  <pre><code>@Controller
  @PreAuthorize("isAuthenticated()")
  @RequestMapping("/assay/designability")
  @SessionAttributes({"assayAssessmentsInitializersBean","assayAssessmentsRequestsDetailsBean"})
  public class AssayDesignabilityController extends AssayBaseController {
  
      @RequestMapping(value = "/uploadFile",method= RequestMethod.GET)
      public String uploadFile(@RequestParam(value = "file")Object file){
          MultipartFile multipartFile=(MultipartFile)file;
  
          logger.info(multipartFile.getName());
          return multipartFile.getName();
      }
  }
  </code></pre>
  
  <p>now when I do all that, the response give me nonsense and when I try to debug I never get to the controller method. any help??</p>
  
  <p><strong>EDIT:</strong>
  now I try to submit it I've updated code and I have the same behavior no response.</p>