function createHttpRequest() {
	if (typeof window.XMLHttpRequest == "undefined") {
		if (typeof window.ActiveXObject == "function") {
			try {
				new ActiveXObject("Msxml2.XMLHTTP");

				window.XMLHttpRequest = function() {
					return new ActiveXObject("Msxml2.XMLHTTP");
				}
			}
			catch (e) {
				try {
					new ActiveXObject("Microsoft.XMLHTTP");
					window.XMLHttpRequest = function() {
						return new ActiveXObject("Microsoft.XMLHTTP");
					}
				}
				catch (e) {
				// 試行を断念する
				}
			}
		}
		// else if (未知のブラウザ) { }
	}
	
	return(new XMLHttpRequest());
}