一、普通文件上传方式

使用原生态的php上传文件。

（1）前端代码

    <form action="upload_file.php" method="post" enctype="multipart/form-data">  
    <label for="file">Filename:</label>  
    <input type="file" name="file" id="file" />   
    <br /><input type="submit" name="submit" value="Submit" />  
    </form>  

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（2）php代码（upload_file.php）

    <?php  
    if ((($_FILES["file"]["type"] == "image/gif")|| ($_FILES["file"]["type"] == "image/jpeg")|| ($_FILES["file"]["type"] == "image/pjpeg"))&& ($_FILES["file"]["size"] < 20000)){  
      if ($_FILES["file"]["error"] > 0) {  
        echo "Return Code: " . $_FILES["file"]["error"] . "<br />";  
      }else {  
          echo "Upload: " . $_FILES["file"]["name"] . "<br />";  
          echo "Type: " . $_FILES["file"]["type"] . "<br />";  
          echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";  
          echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";  
      
          if (file_exists("upload/" . $_FILES["file"]["name"])){  
             echo $_FILES["file"]["name"] . " already exists. ";  
          }else{  
             move_uploaded_file($_FILES["file"]["tmp_name"],  
             "upload/" . $_FILES["file"]["name"]);  
             echo "Stored in: " . "upload/" . $_FILES["file"]["name"];  
          }  
      }  
      
    }else {  
      echo "Invalid file";  
    }  
    ?>  

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二、异步文件上传方式

目的是尽量少使用插件。于是使用iframe异步上传文件

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（1）前端html

    <form id="upForm" action="upload.php" method="post" enctype="multipart/form-data" target="upload_target" >  
      
    导入文件：<input type="file" name="myfile" id="myfile" />  
    <input type="submit" name="submitBtn" value="导入" />  
      
    <iframe id="upload_target" name="upload_target" src="#" style="width:0;height:0;border:0px solid #fff;"></iframe>  
      
    </form>   
    <span id="info"></span>  

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    function startUpload() {  
        var spanObj = document.getElementById("info");  
        spanObj.innerHTML = " 开始上传";  
        document.getElementById("upForm").sumbit();  
    }  
    //回调  
    function stopUpload(responseText){  
        var spanObj = document.getElementById("info");  
        spanObj.innerHTML = "上传成功";  
        spanObj.innerHTML = responseText;  
    }  

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（2）服务器端代码

    $file = $_FILES['myfile'];  
    $fileName = uploadFile($file);  
    //$result = readFromFile("../upload/" . $fileName);  
    echo "<script type='text/javascript'>window.top.window.stopUpload('{$fileName}')</script>";  
      
    function uploadFile($file) {  
        // 上传路径       
        $destinationPath = "../upload/";  
        if (!file_exists($destinationPath)){  
            mkdir($destinationPath , 0777);  
        }  
        //重命名  
        $fileName = date('YmdHis') . '_' . iconv('utf-8' , 'gb2312' , basename($file['name']));  
        if (move_uploaded_file($file['tmp_name'], $destinationPath . $fileName)) {  
            return iconv('gb2312' , 'utf-8' , $fileName);  
        }  
        return '';  
    }  

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    //代码注释  
    /* 
    1，关于basename方法 
    $path = "/testweb/home.php"; 
    //显示带有文件扩展名的文件名 
    echo basename($path); 
    //显示不带有文件扩展名的文件名 
    echo basename($path,".php"); 
     
    2，关于iconv 
    iconv('gb2312' , 'utf-8' , $fileName);//将$fileName从gb2312转为utf-8格式。 
    注：该函数需要开启php.ini里面的php_iconv.dll 
     
    3，关于$_FILES['myfile'] 
    $_FILES相当于一个二维数组，而$_FILES['myfile']相当于一个一维数组。所以可以 
    $f = $_FILES['myfile']; 
    echo $f['name']; 
     
    如果直接访问该$_FILES['myfile']，则会报Undefined index