function require( filename ) {	// The require() statement includes and evaluates the specific file.
	// 
	// +   original by: Michael White (http://crestidg.com)
	// +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
	// %		note 1: Force Javascript execution to pause until the file is loaded. Usually causes failure if the file never loads. ( Use sparingly! )

	var js_code;
	var script_block = document.createElement('script');

	script_block.type = 'text/javascript';
	if(this.is_ie) {
		// moved file_get_contents here to avoid double work
		js_code = this.file_get_contents(filename);
		script_block.text = js_code;
	} else {
		script_block.appendChild(document.createTextNode(js_code));
	}

	if(typeof(script_block) != "undefined") {
		document.getElementsByTagName("head")[0].appendChild(script_block);
		// save include state for reference by include_once
		var cur_file = {};
		cur_file[window.location.href] = 1;

		if (!window.php_js) window.php_js = {};
		if (!window.php_js.includes) window.php_js.includes = cur_file;
		if (!window.php_js.includes[filename]) {
			return window.php_js.includes[filename] = 1;
		} else {
			return window.php_js.includes[filename]++;
		}
	}
}