我有一个运行一些验证的表单。其中一个检查文件是否加载到字段中，以及是否是需要检查的一组复选框

我遇到的问题是，只有当验证被触发时，我的验证才能工作。FF和Chrome都没有给我任何错误。

这是HTML：

<form id="supplier_registration_form" method="POST">
    <label class="block label">stuff:</label>
<br />
    <input name="referenceEmail3" id="referenceEmail3" value="" type="text" />
    <input type="file" name="file_upload1" id="file_upload1" class="fpp_textfield" value="" />
<br />
    <input type="checkbox" name="agency[]" id="one" value="one">
    <label class="block label">one</label>
    <input type="checkbox" name="agency[]" id="two" value="two">
    <label class="block label">two</label>
    <input type="checkbox" name="agency[]" id="three" value="three">
    <label class="block label">three</label>
<br />    
    <input type="submit" name="submit" id="submit" value="Submit">
</form>

这是我的Js验证：

$('#supplier_registration_form').validate({
    onkeyup: false,
    ignore: ":hidden",
    rules: {
        file_upload1: { required: false, accept: "|txt|doc|pdf|docx|xls|xlsx|ppt|pptx"},
        'agency[]': {  required : function() { 
                         var file = document.getElementById("file_upload1").files[0];
                        if (file.size > 0) {
                          return true;
                        } else { 
                          return false; 
                        }
                      }   
                    }    
},
messages: {
  yearEstablished:     'Please enter a year between 1850 and 2013',
  file_upload1:        'Only txt, doc, xcl, xls, ppt and pdf file extensions are allowed!',
  file_upload2:        'Only txt, doc, xcl, xls, ppt and pdf file extensions are allowed!',
  "agency[]":          'One or more certifying agency is required'
},  
onfocusout: function (element) {
  if (!this.checkable(element) && (element.name in this.submitted || !this.optional(element))) {
    var currentObj = this;
    var currentElement = element;
    var delay = function () { 
      currentObj.element(currentElement); 
    };
    setTimeout(delay, 0);
  }
}, 
errorPlacement: function(error, element) {
  if (element.attr("name") == "agency[]" ) 
    error.insertAfter(".certifying-agency-error");
  else 
    error.insertAfter(element);
}
});