Mysql does not execute or produce the warning message on the browser, Warning: mysql_connect() [function.mysql-connect]: Too many connections in ...

Checked in mysql error log file using tail command,

#  tail -f /var/lib/mysql/host3domain.localdomain.err

140326 12:29:27 [ERROR] Error in accept: Too many open files
140326 12:33:43 [ERROR] Error in accept: Too many open files

Files open exceed the amount of file descriptors of the mysql server the default open_files_limit has set  1024,
 
# mysqladmin  variables |grep -i open
| have_openssl                                        | DISABLED
| innodb_open_files                                 | 300
| open_files_limit                                     | 1024
| table_open_cache                                | 400

It is potential to cause  change in /etc/my.cnf.  open the my.cnf file and increase the open_files_limit values.
 
# vi /var/my.cnf

[mysqld]
open_files_limit=5000
...

Then restart the mysql,
 
#/etc/init.d/mysql restart

Now, check the open file limits for mysql,
 
# mysqladmin  variables | grep -i open

| have_openssl                                        | DISABLED
| innodb_open_files                                 | 300
| open_files_limit                                      | 5000
| table_open_cache                                 | 400

OR
 
mysql> show global variables like 'open%';

+------------------+-----------+
| Variable_name    | Value |
+------------------+-----------+
| open_files_limit   | 5000  |
+------------------+-----------+
1 row in set (0.00 sec)

Now, Mysql is running without any issue.