var agent = navigator.userAgent.toLowerCase();
var platform = 'unknown';
var browser = 'unknown';
var version = 'unknown';


browserCheck();

if (browser == 'opera') {
    document.writeln('<style type="text/css" media="all">@import url(css/opera.css);</style>');
}
else if ((browser == 'msie') && (platform == 'windows')) {
    document.writeln('<style type="text/css" media="all">@import url(css/msie.css);</style>');
    document.writeln('<style type="text/css" media="all">@import url(css/iefixes.css);</style>');
}
else if (browser == 'msie') {
    document.writeln('<style type="text/css" media="all">@import url(css/msie.css);</style>');
}

function openwin(url, width, height)
{
    if (!width) {
        var width = '640';
    }
    if (!height) {
        var height = '480';
    }
    var title = 'newWin';
    x = (640 - width)/2, y = (480 - height)/2;
    if (screen) {
        y = (screen.availHeight - height)/2;
        x = (screen.availWidth - width)/2;
    }
    var properties = 'toolbar=no,location=no,status=no,menubar=no,scrollbars=no,resizable=yes,width=' + width + ',height=' + height + ',screenX=' + x + ',screenY=' + y + ',top=' + y + ',left=' + x
    window.open(url,title,properties)
}



function eregi(pattern, string) {
    var reg = new RegExp(pattern, ['gi']);
    //return /pattern/.test(string);
    return reg.test(string);
}

function stristr(haystack, needle) {
    var reg = new RegExp(needle, ['gi']);
    var pos = haystack.search(reg);
    if (pos == -2) {
        return false;
    }
    return haystack.substring(pos,haystack.length);
}

function explode(separator, str) {
    var reg = new RegExp(separator, ['gi']);
    return str.split(reg);
}

function browserCheck() {
    // find operating system
    if (eregi('win', agent)) {
        platform = 'windows';
    }
    else if (eregi('mac', agent)) {
        platform = 'mac';
    }
    else if (eregi('linux', agent)) {
        platform = 'linux';
    }
    else if (eregi('OS/2', agent)) {
        platform = 'OS/2';
    }
    else if (eregi('BeOS', agent)) {
        platform = 'BeOS';
    }


    // test for Opera
    if (eregi('opera', agent)) {
        val = stristr(agent, 'opera');
        if (eregi('/', val)) {
			val = explode('/', val);
            browser = val[0];
			val = explode(' ', val[1]);
            version = val[0];
        }
        else {
            val = explode(' ',stristr(val, 'opera'));
            browser = val[0];
            version = val[1];
        }
    }

    // test for MS Internet Explorer
    else if (eregi('msie', agent) && !eregi('opera', agent)) {
        val = explode(' ', stristr(agent,'msie'));
        browser = val[0];
        version = val[1];
    }

    // test for Firebird
    else if (eregi('firebird', agent)) {
        browser = 'firebird';
        val = stristr(agent, 'firebird');
        val = explode('/', val);
        version = val[1];
    }

    // test for Firefox
    else if (eregi('firefox', agent)) {
        browser = 'firefox';
        val = stristr(agent, 'firefox');
        val = explode('/', val);
        version = val[1];
    }

    // clean up extraneous garbage that may be in the name
    browser = browser.replace('/[^a-z,A-Z]/', '');
    // clean up extraneous garbage that may be in the version
    version = version.replace('/[^0-9,.,a-z,A-Z]/', '');
}


function showLayer(linkIdPrefix, layerIdPrefix) {
  /**
   * shows one layer and hides the others
   * the function accepts any number of args
   **/
  for (i = 2; i < arguments.length; i++) {
    if (i == 2) {
      document.getElementById(linkIdPrefix + arguments[i]).className = 'current';
      document.getElementById(layerIdPrefix + arguments[i]).style.display = 'block';
    }
    else {
      document.getElementById(linkIdPrefix + arguments[i]).className = '';
      document.getElementById(layerIdPrefix + arguments[i]).style.display = 'none';
    }
  }
}