1、js上传验证

js上传验证代码如下：

<?php   
/**  
 * Created by 独自等待  
 * Date: 14-1-22  
 * Time: 下午7:19  
 * Name: upload1.php  
 * 独自等待博客：http://www.waitalone.cn/  
 */  
//文件上传漏洞演示脚本之js验证   
$uploaddir = 'uploads/';   
if (isset($_POST['submit'])) {   
    if (file_exists($uploaddir)) {   
        if (move_uploaded_file($_FILES['upfile']['tmp_name'], $uploaddir . '/' . $_FILES['upfile']['name'])) {   
            echo '文件上传成功，保存于：' . $uploaddir . $_FILES['upfile']['name'] . "n";   
        }   
    } else {   
        exit($uploaddir . '文件夹不存在,请手工创建！');   
    }   
    //print_r($_FILES);   
}   
?>   
<!docTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"  
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   
<html xmlns="http://www.w3.org/1999/xhtml">   
<head>   
    <meta http-equiv="Content-Type" content="text/html;charset=gbk"/>   
    <meta http-equiv="content-language" content="zh-CN"/>   
    <title>文件上传漏洞演示脚本--JS验证实例</title>   
    <script type="text/javascript">   
        function checkFile() {   
            var file = document.getElementsByName('upfile')[0].value;   
            if (file == null || file == "") {   
                alert("你还没有选择任何文件，不能上传!");   
                return false;   
            }   
            //定义允许上传的文件类型   
            var allow_ext = ".jpg|.jpeg|.png|.gif|.bmp|";   
            //提取上传文件的类型   
            var ext_name = file.substring(file.lastIndexOf("."));   
            //alert(ext_name);   
            //alert(ext_name + "|");   
            //判断上传文件类型是否允许上传   
            if (allow_ext.indexOf(ext_name + "|") == -1) {   
                var errMsg = "该文件不允许上传，请上传" + allow_ext + "类型的文件,当前文件类型为：" + ext_name;   
                alert(errMsg);   
                return false;   
            }   
        }   
    </script>   
<body>   
<h3>文件上传漏洞演示脚本--JS验证实例</h3>   
  
<form action="" method="post" enctype="multipart/form-data" name="upload" onsubmit="return checkFile()">   
    <input type="hidden" name="MAX_FILE_SIZE" value="204800"/>   
    请选择要上传的文件：<input type="file" name="upfile"/>   
    <input type="submit" name="submit" value="上传"/>   
</form>   
</body>   
</html>

上传php文件被阻断