Removed addEvent support
Removed addEvent support

As noted in #456, IE8 is no longer supported.

Also, undefined is falsey in JavaScript, so the typeof check was unnecessary.
carl-alberto/business-portfolio,jchck/jchck_,vaishaliagola27/_s,vaishaliagola27/_s,vaishaliagola27/_s,andbaz/launchbaz,SparkartGroupInc/nadando,andbaz/launchbaz,jchck/jchck_,solidusjs/wp-solidus,carl-alberto/business-portfolio,madeso-uk/vcsassist,madeso-uk/vcsassist