function is_valid_string(str){
	var rvalue = true;
	var pattern = '^[a-zA-Z0-9ß-üÖÜÄ\s:!$&@_\.\-]+$';
	var regex = new RegExp(pattern);
	if(!regex.test(str)){
		rvalue = false;
	}
	return rvalue;
}

function utf8_decode (str_data) {
	i = 0,
	ac = 0,
	c1 = 0,
	c2 = 0, c3 = 0;
 
    str_data += '';
	var tmp_arr = new Array();
    while (i < str_data.length) {        c1 = str_data.charCodeAt(i);
        if (c1 < 128) {
            tmp_arr[ac++] = String.fromCharCode(c1);
            i++;
        } else if (c1 > 191 && c1 < 224) {            c2 = str_data.charCodeAt(i + 1);
            tmp_arr[ac++] = String.fromCharCode(((c1 & 31) << 6) | (c2 & 63));
            i += 2;
        } else {
            c2 = str_data.charCodeAt(i + 1);            c3 = str_data.charCodeAt(i + 2);
            tmp_arr[ac++] = String.fromCharCode(((c1 & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
            i += 3;
        }
    } 
    return tmp_arr.join('');
}