Questions about PHP beginners! Thank you!

PHP beginner question !! Thank you !! I learned about an open-source project on the internet. the only place for registration and verification is a bit problematic. I don't know what went wrong. JS calls php file verification but does not know why it returns 0 and does not know why there is an error. JS code: functionchkname (form) {if (form. na PHP beginner question !! Thank you !!
I learned about an open-source project on the internet. the only place for registration and verification is a bit problematic. I don't know what went wrong.
JS calls PHP file verification but does not know why it returns 0 and does not know why there is an error.

JS code:
Function chkname (form ){
If (form. name. value = "")
{
Name1.innerHTML = "enter the user name! ";
}
Else
{
Var user = form. name. value;

Var url = "chkname. php? User = "+ user;

XmlHttp. open ("GET", url, true );
XmlHttp. onreadystatechange = function ()
{

If (xmlHttp. readyState = 4)
{
Var msg = xmlHttp. responseText;
If (msg = '2 '){
Name1.innerHTML = "the user name is occupied! ";
Return false;
} Else if (msg = '1 '){
Name1.innerHTML = "Congratulations, you can register! ";
Form. c_name.value = "yes ";

} Else {
Name1.innerHTML = "" + msg + "";
}
}
}
XmlHttp. send (null );
}
}

PHP code: Session_start ();
Include_once "conn/conn. php ";
$ Reback = '0 ';
$ SQL = "select * from tb_user where name = '". $ _ GET ['user']. "'";
$ Rst = $ conn-> Execute ($ SQL) or die ('execute error ');
If ($ rst-> RecordCount () = 0)
{

$ Reback = '1 ';
}
Else
{
$ Reback = '2 ';
}
Echo $ reback;
?>


------ Solution --------------------
Discussion
$ Rst = $ conn-> Execute ($ SQL) or die ('execute error ');
If ($ rst-> RecordCount () = 0)

------ Solution --------------------
"Php ajax registration Source Code"
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