这段 ASP源码用PHP怎么写，求指教！

Question

<%
dim t1
dim t2
dim t3
dim t4t1=request.form("t1")
t2=request.form("t2")
t3=request.form("t3")
t4=request.form("t4")
if request.form("t1")="" then
response.write "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
response.end
end ifif request.form("t2")="" then
response.write "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
response.end
end if
if request.form("t3")="" then
response.write "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
response.end
end if
if request.form("t4")="" then
response.write "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
response.end
end ifelement="********************************"
sj=now()
set fso=server.createobject("scripting.filesystemobject") 
set fc=fso.openTextFile(server.mappath("zl.txt"),8,true) 
fc.writeline (t1) 
fc.writeline (t2) 
fc.writeline (t3)
fc.writeline (t4)fc.writeline (sj) 
fc.writeline (element) 
fc.close 
set fc=nothing 
set fso=nothing response.write "<script>alert('提交成功,');window.history.go(-1);</script>"
response.Redirect "http://www.qq.com"
%>

Answer 1

$t1=$_POST["t1"];
$t2=$_POST["t2"];
$t3=$_POST["t3"];
$t4=$_POST["t4"];
if ($t1==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
if ($t2==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
if ($t3==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
if ($t4==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}$content = ;
file_put_contents('zl.txt',"$t1\n$t2\n$t3\n$t4\n".date('Y-m-d H:i:s')."\n********************************\n",FILE_APPEND);
echo "<script>alert('提交成功,');window.history.go(-1);</script>"

Answer 2

$t1=$_POST["t1"];
$t2=$_POST["t2"];
$t3=$_POST["t3"];
$t4=$_POST["t4"];
if ($t1==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
if ($t2==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
if ($t3==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
if ($t4==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}file_put_contents('zl.txt',"$t1\n$t2\n$t3\n$t4\n".date('Y-m-d H:i:s')."\n********************************\n",FILE_APPEND);
echo "<script>alert('提交成功,');window.history.go(-1);</script>"

Answer 3

简化的extract($_POST);
if ($t1=="" || $t2=="" || $t3=="" || $t4==""){
echo "<script>alert('同学 不能留空！!');window.history.go(-1);</script>"
exit;
}
$content = ;
file_put_contents('zl.txt',"$t1\n$t2\n$t3\n$t4\n".date('Y-m-d H:i:s')."\n********************************\n",FILE_APPEND);
echo "<script>alert('提交成功,');window.history.go(-1);</script>"