document.addEventListener('DOMContentLoaded', function (event){
var commentForm=document.getElementById("commentform");
if(null===commentForm){
return;
}
var author=commentForm.querySelector("#author");
if(null===author){
return;
}
author.addEventListener('blur',
function (){
this.value=this.value.replace(/\d+/g, '');
},
false
);
});