function addResDigitaOrg (id) { document.getElementById(id).value = document.getElementById(id).value.split("@")[0] + "@resdigita.org"; return document.getElementById(id).value; } function addResDigitaOrgIdValue () { document.getElementById("mail").value = addResDigitaOrg("idvalue"); } function addResDigitaOrgMail () { document.getElementById("idvalue").value = addResDigitaOrg("mail"); } document.getElementById("idvalue").addEventListener("change",addResDigitaOrgIdValue);