<Select> data transmission problems

&Lt;select&gt;data transmission question inquire.html & lt; html & gt; & lt; head & gt; & nbsp; & lt; title & gt; inquiretheclassroom & lt;/title & gt; & lt; /head & gt; & lt; body & Data transmission problemsInquire.htmlInquire the classroomCRMS-Inquire the classroomInquire_classroom.phpInquire the classroomCRMS-Inquire the classroom // Create short variable names$ Lesson_id = $ _ POST ['lesson _ id'];$ Con = mysql_connect ("localhost", "root ","");// Establish a connection through the server locahost. the user name is root and no password is required.If (! $ Con){Die ('could not connect: '. mysql_error ());} // If it fails, an error is displayed.Mysql_select_db ("crms", $ con); // select a databaseIf (! Mysql_select_db ("crms", $ con) die (mysql_error ());$ Search_lesson_id = "SELECT * FROM use2 WHERE lesson_id = '{$ lesson_id }'";$ Result = mysql_query ($ search_lesson_id, $ con );If (! $ Result){Die ("The lesson does not exist .");}While ($ row = mysql_fetch_array ($ result )){Echo $ row ['cno'];Echo $ row ['CID'];Echo"";}Mysql_close ($ con );?>After a value is selected in the drop-down box and submittedNotice: Undefined index: lesson_id in D: \ xampp \ htdocs \ inquire_classroom.php on line 9D301001 error. But hereHave I already defined it?


------ Solution --------------------
$ Lesson_id = $ _ POST ['lesson _ id']; this is actually OK.
Modify the error severity of php. ini:
Error_reporting = E_ALL &~ E_NOTICE

Restart apache after modification.
------ Solution --------------------
Notice is not an error and does not affect the result.
If notice is not displayed, modify the error prompt level in php. ini.