i18n

var currLang = i18n.getCurrentLanguage();

// returns 'Welcome my_name in my solution'
// if the key 'mykey.username.text' is 'Welcome {0} in my solution'
i18n.getI18NMessage('mykey.username.text',new Array('my_name'))

// returns 'Welcome my_name in my solution'
// if the key 'mykey.username.text' is 'Welcome {0} in my solution'
i18n.getI18NMessage('mykey.username.text',new Array('my_name'))

//sets the value of i18n key for client scope; if value null the setting is removed
//Warning: already created form elements with i18n text lookup will not change,
//so call this method in the solution startup method or in methods from first form
//this method saves message for current locale, so if locale is changed with setLocale, all messages set from scripting will be lost

i18n.setI18NMessage('mykey.username.text','my_name')

//Warning: already created form elements with i18n text lookup will not change,
//so call this method in the solution startup method or in methods from first form

i18n.setLocale('en','US');