使用PHP进行文件上传，主要使用到表单功能和ＰＨＰ内置的$_FILES函数功能。接下来我们看如何实现ＰＨＰ上传功能。例子效果图，此例子是在Mac下进行调试成功的。
PHP上传图片文件的功能代码如下：
<html>
<head>
<meta charset="utf-8">
<title>Upload File Example</title>
<style>
body{
width:500px;
margin:20px auto;
line-height:25px;
}
img{
display:block;
max-width:500px;
}
h1{
text-align:center;
}
#uploadfile{
background-color:#eee;
text-align:center;
width:500px;
margin:0 auto;
}
form{
margin:0px;
padding:0px;
}
#uploadfile .input1{
display:block;
width:500px;
text-align:center;
margin:0 auto;
}
#uploadfile .input2,.input3{
width:100px;
margin:5px 20px;
}
</style>
</head>
<body>
<h1>Upload File</h1>
<div id="uploadfile">
<form enctype="multipart/form-data" action="<?php echo $_SERVER['PHP_SELF'];?>" method="post">
<input class="input1" name="upfile" type="file">
<input class="input2" type="submit" value="确认提交">
<input class="input3" type="reset" value="重置">
</form>
</div>
<?php
if($_FILES["upfile"]["name"]==NULL){
echo "No file choice!";
}else{
$filepath="/Library/WebServer/Documents/";
$tmp_name=$_FILES["upfile"]["tmp_name"];
$filename=$filepath.$_FILES["upfile"]["name"];
echo "<br>"."\$_FILES['upfile']['name']:".$_FILES["upfile"]["name"];
echo "<br>"."\$_FILES['upfile']['size']:".GetSize($_FILES["upfile"]["size"]);
echo "<br>"."\$_FILES['upfile']['type']:".$_FILES["upfile"]["type"];
echo "<br>"."\$_FILES['upfile']['tmp_name']:".$_FILES["upfile"]["tmp_name"];
if(move_uploaded_file($tmp_name,$filename)){
echo "<br>"."已上传至目录：".$filename;
if(in_array($_FILES["upfile"]["type"],array("image/png","image/jpg","image/bmp"))){
echo "<br>"."<img src='/".$_FILES["upfile"]["name"]."' />";
}else{ }
}else{
echo "<br>"."Upload faild!";
}
}
// 将文件大小转成相应计量单位
function GetSize($tmp){
$arr = array("B","KB","MB","GB","TB","PB");
$pos = 0;
if(!is_integer($tmp))
return -1;
while($tmp>1024 and count($arr)>$pos){
$tmp = $tmp / 1024.0;
$pos++;
}
$tmp = sprintf("%.2f",$tmp);
return $tmp.$arr[$pos];
}
?>
</body>
</html>
使用表单的action可以选点表单提交对象，象本文中的例子是将表单提交给自己进行处理。
method可以选择post或get文件进行提交。