var name_2 = "fo";
var name_1 = "in";
var domain_1 = "taryx";
var domain_2 = "com";

document.write("<a href=mailto:" + name_1 + name_2 + "@" + domain_1 + "." + domain_2 + ">");
document.write(name_1 + name_2 + "@" + domain_1 + "." + domain_2 + "</a>");