ucwords() for JavaScript

js-ucwords

// The unicode-safe ucwords() func for JS (to capitalize the first characters of words),
// which additionally respects double-lastnames like Russian Засс-Ранцев and weird French names,
// like Honoré de Balzac and d'Artagnan.

String.prototype.ucwords = function() {
  return this.toLowerCase()
    .replace(/(^|\s|\-)[^\s$]/g, function(m) {
       return m.toUpperCase();
    })
    // French, Arabic and some noble names...
    .replace(/\s(Of|De|Van|Von|Ibn|Из|Ван|Фон|Ибн)\s/g, function(m) { // Honoré de Balzac, Vincent van Gogh, Otto von Bismarck, Sulaymān ibn Dāwūd etc.
       return m.toLowerCase();
    })
    .replace(/(^|\s)(D|Д)(['’][^\s$])/g, function(m, p1, p2, p3) { // D'Artagnan or d'Artagnan / Д’Артаньян или д’Артаньян
       return p1 + (p1 === "" ? p2/*.toUpperCase()*/ : p2.toLowerCase()) + p3.toUpperCase();
    });
}

// Usage (best if used together with "text-transform: capitalize"):
// <input onBlur="this.value = this.value.ucwords()" style="text-transform: capitalize" />