限制上传文件类型程序代码

<script>
function check(){
var filepath=path.value
filepath=filepath.substring(filepath.lastIndexOf('.')+1,filepath.length)
if(filepath != 'jpg' && filepath != 'gif')
alert("只能上传JPG或GIF格式的图片")
}
</script>

<input type=file name=path onpropertychange="check()"> (只能上传JPG或GIF格式的图片)

<script>
function ck(obj){if(obj.value.length>0){
var af="jpg,gif,png,zip,rar,txt,htm";
if(eval("with(obj.value)if(!/"+af.split(",").join("|")+"/ig.test(substring(lastIndexOf('.')

+1,length)))1;")){alert("Allowed file types:n"+af);obj.createTextRange().execCommand('delete')};
}}
</script>
<form>
<input type=file name=path onpropertychange="ck(this)"/></form>

/*
 * 判断图片类型
 *
 * @param ths
 *    type="file"的javascript对象
 * @return true-符合要求,false-不符合
 */
function checkImgType(ths){
 if (ths.value == "") {
  alert("请上传图片");
  return false;
 } else {
  if (!/.(gif|jpg|jpeg|png|GIF|JPG|PNG)$/.test(ths.value)) {
   alert("图片类型必须是.gif,jpeg,jpg,png中的一种");
   ths.value = "";
   return false;
  }
 }
 return true;
}

$name=$_FILES['file4']['name']; //获取客户端机器原文件的名称
$type=strstr($name,"."); //获取从"."到最后的字符 if($type!=".txt")
{ echo "对不起,您上传文件的格式不正确!!";
echo "<meta http-equiv="Refresh" content="3;url=index.php?lmbs=文件上传">将在3秒钟后返回前页...";
}

$temppath=$upfile['tmp_name'];
$fileinfo=pathinfo($upfile['name']);
$extension=$upfile['type'];
switch( $extension )
{
    case 'application/msword':
    $extension ='doc';
    break;
    case 'application/vnd.ms-excel':
    $extension ='xls';
    break;
    case 'application/vnd.openxmlformats-officedocument.wordprocessingml.document':
    $extension ='docx';
    break;
    case 'application/vnd.ms-powerpoint':
    $extension ='ppt';
    break;
    case 'application/pdf':
    $extension ='pdf';
    break;
    case 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet':
    $extension ='xlsx';
    break;
    default:
    die('只允许上传doc,docx,xls,pdf,ppt文件 <a href="wend.php">重新上传</a>');
   
 }