Biker John questions

• User agent, extract OS and browser from string
• Append & prepend string to existing rows
• Custom 404 shows "File not found" for php files instead of redirecting
• Attribute Error: next()
• MySQL select random row - rand() performance [duplicate]
• MySQL triple join
• Calculate color values from green to red
• Count and limit the number of files uploaded (HTML file input)
• Position:absolute causes horizontal scrollbar

Biker John answers