js编写的浏览上传文件

<div style="position:relative;width:380px;">
            <iframe id="t_load" name="t_load" style="display: none"></iframe>
            <form action="" method="post" enctype="multipart/form-data" name="form1" target="t_load">
                <input type=‘text‘ name=‘textfield‘ id=‘textfield‘ style="height:22px; border:2px solid #cdcdcd; width:230px; border-radius:50px;" />
                <input type=‘button‘ value=‘浏览...‘ style="display: inline-block;
  margin-bottom: 0;
  font-size: 14px;
  border-radius: 4px;
padding: 6px 12px;
  margin: 2px 2px;
  border: 1px solid #357ebd;
  background: #1b9ad5;
  color: #fff;" />
                <input type="file" name="file1" accept="image/jpeg, image/gif" id="file1" onchange="document.getElementById(‘textfield‘).value=this.value" style="position:absolute; top:5px; right:74px; height:27px; filter:alpha(opacity:0);opacity: 0;width:300px" />

                <input type="button" name="button" onclick="mysubmit()" value="上传" style="display: inline-block;
 margin-bottom: 0;
  font-size: 14px;
  border-radius: 4px;
padding: 6px 12px;
  margin: 2px 2px;
  border: 1px solid #357ebd;
  background: #1b9ad5;
  color: #fff;">
            </form>
        </div>
        <div style="display:none;color:#6D6D72;font-size: 20px;" id="res"></div>

<script>
            function mysubmit() {
                var a = document.getElementById("textfield").value;

                if(a == "") {
                    alert("请上传文件");
                    return;
                }
                document.form1.submit();
                ajaxsend();
            }

            function ajaxsend() {

                var xmlHttp;
                if(window.ActiveXObject) {
                    xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
                } else {
                    xmlHttp = new XMLHttpRequest();
                }
                xmlHttp.open("post", "upload", true);
                xmlHttp.onreadystatechange = function() {
                    xmlHttp.readyState;
                    if(xmlHttp.readyState == 4) {
                        res.innerHTML = "上传成功！";
                        setTimeout(function() {
                            res.innerHTML = "";
                        }, 2000);

                    } else {
                        document.getElementById("res").style.display = "inline";
                    }
                }
                xmlHttp.send();
                var obj = document.getElementById(‘textfield‘);

                obj.outerHTML = obj.outerHTML;

            }
        </script>