What is in JavaScript 1.5? JavaScript 1.5 adheres to ECMA-262, revision 3 (See the JavaScript futures page for a link to the spec.) created by the ECMA Technical Committee TC39. New features include: ECMA 3 Features Runtime errors reported as exceptions. Number formatting (Number.prototype.toFixed and Number.prototype.toExponential) Regular Expression Enhancements. Additional Features (SpiderMo