PHP跨网域跨主机跨server上传文件实例教程

<?php
$file = $_FILES[&#39;file&#39;]; 
$file_tmp = $file[&#39;tmp_name&#39;]; 
$file_name = $file[&#39;name&#39;]; 
if(is_uploaded_file($file_tmp)){ //确定user有"上传"文件 
$file_ext = strrchr($file_name,&#39;.&#39;); //上传文件的副文件名 
$file_name_new = date(&#39;YmdHis&#39;).$file_ext; 
$host = &#39;127.0.0.1&#39;; 
$port = &#39;21&#39;; 
$user = &#39;admin&#39;; 
$pass = &#39;123456&#39;; 
$link = ftp_connect($host,$port); 
$login = ftp_login($link,$user,$pass); 
ftp_chdir($link,&#39;filedir&#39;); //切换到要放文件的文件夹 
if(ftp_put($link,$file_name_new,$file_tmp,FTP_BINARY)){ 
    $msg = &#39;上传成功&#39;;   
}else{ 
    $msg = &#39;上传失败&#39;; 
} 
}else{ 
    $msg = &#39;上传失败&#39;; 
} 
ftp_close($link); 
echo $msg;