40. Write Simple Regular Expressions

1. Matching age: between 18 and 65

　　var reg = / ^ [] $ / 

Knowledge points:

　　1) Two digits are not recognized in brackets in []

　　var reg = /^[12]$/ // one of 1 or 2 

　　var reg = /^[12-68]$/ // 1, one of 2-6, 8 one of three

　　var reg = /^[\w-]$/; // one of number, letter, underscore, -

　　console.log(reg.test("-"))// true