<form action="test.php" method="post" enctype="multipart/form-data">
    <input type="file" name="myfile">
    <input type="submit" value="上傳">
  </form>

<input type="hidden" name="MAX_FILE_SIZE" value="8096">
<input type="file" name="myfile" accept="image/jpeg,image/png">

<?php
  header('Content-type:text/html;charset=utf-8');
  $myfile=$_FILES['myfile'];
  //獲取文件數(shù)組['myfile']的屬性tmp_name與name
  $tmp=$myfile['tmp_name'];
  $picname=$myfile['name'];
  //windows采用GBK編碼，php采用utf-8編碼，需要改變文件名的編碼格式
  $picname=iconv('utf-8','GBK',$picname);
  //將零時(shí)文件$tmp移動(dòng)到指定目錄userpic并命名為$picname
  copy($tmp,"userpic/".$picname);

$error=$myfile['myfile']['error'];
  if ($error==0){//為0，代表上傳成功
    if (move_uploaded_file($tmp,"userpic/".$picname)) {
      echo "移動(dòng)文件成功";
    }else{
      echo "移動(dòng)文件失敗";
    }
  }else{//不為0，匹配錯(cuò)誤信息
    switch ($error){
      case 1:
        echo "超過文件最大上傳限制";//php.ini中upload_max_filesize
        break;
      case 2:
        echo "超過表單文件大小限制";//HTML表單中MAX_FILE_SIZE選項(xiàng)
        break;
      case 3:
        echo "文件部分被上傳";
        break;
      case 4:
        echo "未選擇上傳文件";
        break;
      case 7://文件寫入失敗
      case 8:
        echo "系統(tǒng)錯(cuò)誤";
        break;
    }
  }

<!--表單隱藏域?qū)ι蟼鞔笮∵M(jìn)行限制-->
<input type="hidden" name="MAX_FILE_SIZE" value="2097152">
<!--accept 對文件類型限制-->
<input type="file" name="myfile" accept="image/jpeg,image/png">

$size=$myfile['size'];//獲取文件大小
$MaxSize=2097152;//設(shè)置最大允許字節(jié)
$type=$myfile['type'];//獲取圖片類型
$AllowTypr=array('image/jpeg','image/png','image/gif');//允許類型數(shù)組
if ($error==0){//為0，代表上傳成功
  if ($size>$MaxSize){
    echo "<script>alert('文件大小超過限制');</script>";
    echo "<script>history.back(1);</script>";
    exit();
  }
  if (!in_array($type,$AllowTypr)){
    echo "<script>alert('請上傳正確圖片類型');</script>";
    echo "<script>history.back(1);</script>";
    exit();
  }