Header ("Location:empManage.php") page jumps to the blank page, solves, how to deal with

Header ("Location:empManage.php") page jumps to a blank page, solving
loginprocess.php:


Accept user's data
1.id
$id =$_post["id"];
2. Password
$password =$_post["Password"];

To the database to verify the MySQL extension library mysqli Extension Library
1. Get Connected
$conn =mysql_connect ("localhost", "root", "root");

if (! $conn) {
Die ("link Failed". Mysql_errno ());
}
Set the encoding for accessing the database
mysql_query ("Set names Utf-8", $conn) or Die (Mysql_errno ());
Select Database
mysql_select_db ("Empmanage", $conn) or Die (Mysql_errno ());

Send SQL statements to verify
Prevent SQL injection attacks, change validation logic
$sql = "Select password from admin where id= $id";

Obtain the password for the database by entering the ID, and then compare the password with the input.
$res =mysql_query ($sql, $conn);

if ($row = Mysql_fetch_assoc ($res)) {
Query to
Remove Database Password
if ($row ["Password"]== MD5 ($password))) {
Description Legal
Header ("Location:empManage.php");

}

}
Header ("Location:login.php?errno=1");
Exit ();



Mysql_free_result ($res);
Mysql_close ($conn);


/*
Simple validation (less than database)
if ($id = = "+" && $password = = "123") {
Legal, jump to empmanage.php
Header ("Location:empManage.php");
If you want to jump, it's best to exit ()
Exit ();
}else{
Illegal users
Header ("Location:login.php?errno=1");
Exit ();
}
*/
?>


Code as above, do not connect to the database can normally jump to empmanage.php
Connected to the database after the blank page, jump to the page is loginprocess.php itself, how to ah, online and other answers!!

------Solution--------------------
No output before header ();
Must be placed in front of the page head;
According to the landlord's question, check:
Whether the database can be connected properly;
The encoding is consistent;
$row ["Password"] and MD5 ($password) have equal values
------Solution--------------------
I do not see any error in the code, it is recommended that you debug first to see. Change the header () to Echo (); See if there's any output. Also, see if you have an open error prompt
------Solution--------------------
$res =mysql_query ($sql, $conn);
This sentence is not wrong.
May cause if ($row = Mysql_fetch_assoc ($res)) {There is a mistake, because the error display is not open, so it is a blank page

------Solution--------------------
Explore

$res =mysql_query ($sql, $conn);
This sentence is not wrong.
May cause if ($row = Mysql_fetch_assoc ($res)) {There is a mistake, because the error display is not open, so it is a blank page

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