var emailRegex =/^(?("")(""[^""]+?""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)
(?<=[0-9a-z])@))(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9]{2,24}))$/ 
above pattern for email validations giving Error:
")" is not valid at the start of a code block. 
 Only identifiers, keywords, comments, "(" and "{" are valid.   
 
     
     
     
    