One-time function initializations

gistfile1

// Simply wrap the return value in an immediate function
// and return the result. The below example implements // a test for HTML5 WebSocket Feature detection; however,
// the same concept applies for any function initializer.
var hasWebSockets = ( function (window) {
    var prefixes = 'ms O Moz Webkit'.split (' ')
     ,  n = prefixes.length
     ,  i = 0;
    for (; i < n; ++i) {
        if ( window [prefixes [i] + 'WebSocket'] ){
            return true;
        }
    }
    return 'WebSocket' in window;
}( this ));