//variables
var user = "ledread"; 
var domain = "annuaire-x.com"; 
var subject = "Contact - Annuaire X.com"; 
var bodytext = "Ecrivez votre message ici"; 

//output
document.write('<a href=\"mailto:' + user + '@' + domain + '?subject=' + subject + '&body=' + bodytext + '\" class=\"col\">'); 
document.write('Contact</a>');