!DOCTYPE html>
html lang="en">
head>
  meta charset="UTF-8">
  title>Title/title>
  script type="text/javascript" src="__PUBLIC__/home/js/jquery-1.11.0.js">/script>

/head>
body>
form class="form-horizontal" role="form" id="myForm"
   action="/index/fileupsend" method="post"
   enctype="multipart/form-data">

  选择文件:input type="file" id="file1" />br />
  input type="button" id="upload" value="上传" />
  span id="imgWait">/span>
/form>
script>
  $(function () {
    $("#upload").click(function () {
      $("#imgWait").html("上传中");
      var formData = new FormData();
      formData.append("myfile", document.getElementById("file1").files[0]);
      $.ajax({
        url: "/Home/index/fileupsend",
        type: "POST",
        data: formData,
        /**
         *必须false才会自动加上正确的Content-Type
         */
        contentType: false,
        /**
         * 必须false才会避开jQuery对 formdata 的默认处理
         * XMLHttpRequest会对 formdata 进行正确的处理
         */
        processData: false,
        success: function (data) {
          if(data){
            alert("上传成功！");
          }
          $("#imgWait").html("上传成功");

        },
        error: function () {
          alert("上传失败！");
          $("#imgWait").hide();
        }
      });
    });
  });
/script>
/body>
/html>

public function fileupsend(){
  $type_pic = $this->file_upload('1',array('jpg', 'gif', 'png', 'jpeg'),'filetest','myfile');
  echo $type_pic['img_path'];

}