js动态创建上传表单通过iframe模拟Ajax实现无刷新

<script> 
window.onload=function(){ 
upfile('file.php'); 
} 
/* 
** url 路径 
**/ 
function upfile(url){ 
//创建iframe 
var iframe = document.createElement("iframe"); 
document.body.appendChild(iframe); 
iframe.id = 'iframeName'; 
iframe.name = 'iframeName'; 
iframe.style.display = 'none'; 
//创建form 
var turnForm = document.createElement("form"); 
document.body.appendChild(turnForm); 
turnForm.method = 'post'; 
turnForm.action = url; 
turnForm.encoding = "multipart/form-data"; 
turnForm.name = 'formNamer'; 
turnForm.target = 'iframeName'; 
//创建隐藏表单 
var newElement = document.createElement("input"); 
newElement.setAttribute("name","inputname"); 
newElement.setAttribute("type","file"); 
newElement.setAttribute("value",''); 
turnForm.appendChild(newElement); 
} 
//form提交 
function formSubmit() { 
//var res = document.formNamer.inputname.value; 
document.formNamer.submit(); 
} 
//返回值 
function callback(result){ 
//window.parent.document.getElementById('iframeName').style.display = 'block'; 通过iframe 查看后台数据 
if(result['error'] == 0){ 
document.getElementById('test').src= result['img'][1]+'/'+result['img'][2]; 
}else if(result['error'] == 1){ 
alert(result['meg']); 
}else if(result['error'] == 2){ 
alert(result['meg']); 
}else if(result['error'] == 3){ 
alert(result['meg']); 
}else if(result['error'] == 4){ 
alert(result['meg']); 
}else{ 
alert(result['meg']); 
} 
} 
</script> 
<a href="javascript:formSubmit()">上传</a> 
<img src="http://blog.163.com/zhwxl_zyx/blog/img/pasic.jpg" id="test" width="200" height="200">

file.php

<?php 
header("content-Type: text/html; charset=Utf-8"); if(@is_uploaded_file($_FILES['inputname']['tmp_name'])){ 
$f = $_FILES['inputname']; 
$name = $f["name"]; 
$size = $f["size"]; 
$type = $f["type"]; 
$fileName = $f["tmp_name"]; 
switch ($type) { 
case 'image/jpg':$okType = true; 
break; 
case 'image/jpeg':$okType = true; 
break; 
case 'image/png':$okType = true; 
break; 
case 'image/gif':$okType = true; 
break; 
} 
if($okType){ 
$error = $f["error"]; 
echo '文件名称:'.$name.'<br>'; 
echo '文件类型:'.$type.'<br>'; 
echo '文件大小:'.round($size/1024).'K<br>'; 
echo '文件临时存放路径:'.$fileName.'<br>'; 
$fileDir = dirname(__FILE__).'/img/upfile'.time().$name; 
$img = explode('/',$fileDir); 
move_uploaded_file($fileName, $fileDir); 
$data = array(); 
$data['img'] = $img; 
$data['name'] = $name; 
$data['type'] = $type; 
$data['size'] = $size; 
$data['filename'] = $fileName; 
$data['fileDir'] = $fileDir; 
if($error==0){ 
/*echo '上传成功!'; 
echo '预览:'; 
echo "<img src="http://blog.163.com/zhwxl_zyx/blog/.$img[1].'/'.$img[2]." width='200' height='200'><br>"; 
echo '文件名称'.$img[2];*/ 
$data['error'] = 0; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
}elseif($error==1){ 
$data['error'] = 1; 
$data['meg'] = '超过了文件大小，在php.ini文件中设置'; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
}elseif ($error==2){ 
$data['error'] = 2; 
$data['meg'] = '超过了文件的大小MAX_FILE_SIZE选项指定的值'; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
}elseif ($error==3){ 
$data['error'] = 3; 
$data['meg'] = '文件只有部分被上传'; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
}elseif ($error==4){ 
$data['error'] = 4; 
$data['meg'] = '没有文件被上传'; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
}else{ 
$data['meg'] = '上传文件大小为0'; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
} 
} 
}else{ 
$data['error'] = 4; 
$data['meg'] = '没有文件被上传'; 
exit("<script>parent.callback(".json_encode($data).");</script>"); 
} 
?>