The following sets the target to _blank:
if (key == \"smk\") {
window.location = \"http://www.smkproduction.eu5.org\";
target = \"_blank
window.location sets the URL of your current window. To open a new window, you need to use window.open. This should work:
function ToKey(){
var key = document.tokey.key.value.toLowerCase();
if (key == "smk") {
window.open('http://www.smkproduction.eu5.org', '_blank');
} else {
alert("Kodi nuk është valid!");
}
}