... The!HTML!submit!input!type!is!given!a!name,!submit_fare,!that!will!be!used!in!the!following !PHP! script. 4 The!opening !PHP! tag!tells !PHP! to!start!processing. 5 Now!we!are!looking!at!the !PHP! instructions.!If!the!user!pressed!the!submit!button,!this!file!will!execute. !PHP! will!store!the!names!of!the!input!devices!in!variables,!$age !and! $submit_fare.!This!conditional!expression!tests!to!see!if!those!variables!were!set.!If!they!weren’t!set,!then!the!form!was!either!not!submitted!or!the!user!left!it!empty,!or!both. ... special significance and those characters are represented by HTML entities, special symbols starting with an ampersand and terminated with a semicolon; for example, the < and > symbols are ... In!the!switch!expression,!the!value!of!$color!is!matched!against!the!values!of!each!of!the!following!case!labels.! (PHP! names!the!variable,!$color, !by! the!same!name!assigned!to!the!radio!button !and! assigns!to!the!varia b le!the!value!that!was!selected !by! the! user!when!he!or!she!clicked!the!button.!If!the!user!clicked!red,!then!$color!will!evaluate!to!red.)!See!Figures!7.6 !and! 7.7....