php文件上传函数

<?php
/**
+++++++++++++++++++++=+++++上传图片++++++++++++++++++++++++++++++++++++++++
——————————————————————————————————————————————————————————————————————————————————

**/
function upload_image($key,$dir) {

$fname = $_FILES[$key]['name'];
$ftype = $_FILES[$key]['type'];
$fsize = $_FILES[$key]['size'];
$ftmpl = $_FILES[$key]['tmp_name'];
$ferror = $_FILES[$key]['error'];

$imagetype = array("image/jpeg","image/jpg","image/gif","image/pjpeg");
if($ferror==2 or $ferror==1) {
echo '<script>alert("图片过大");history.go(-1);</script>';
exit;
}
if(!is_uploaded_file($ftmpl)){
echo '<script>alert("上传图片失败，请稍后重试1");history.go(-1);</script>';
exit;
}
$is_true = in_array($ftype,$imagetype);
if(!$is_true) {
echo '<script>alert("图片格式不正确");history.go(-1);</script>';
exit;
}
if($fsize>2*(1024*1024)) {
echo '<script>alert("图片过大");history.go(-1);</script>';
exit;
}
if(!file_exists($dir)) {
mkdir($dir);
}
$fname = time().$fname;
if(!move_uploaded_file($ftmpl,$dir.$fname)) {
echo '<script>alert("上传图片失败，请稍后重试2");history.go(-1);</script>';
exit;
}
return $fname;
}
?>