HtmlTag attr(String name, String value) {
        if (attrs == null) {
            attrs = new HashMap<>();
        }
        attrs.put(name, value);
        return this;
    }
HtmlTag attr ( String name , String value ) { if ( attrs == null ) { attrs = new HashMap < > ( ) ; } attrs . put ( name , value ) ; return this ; }
Attribute name and value are not escaped or modified in any way.

@param name
@param value
@return self