
/*
  To implement this script in your Web page, configure this file as
  shown below, then put this file on your Web server.

  Next, insert the following at the beginning of the <head> section
  of your Web page:

    <script type="text/javascript" language="JavaScript1.2" src="[path]efa_fontsize.js"></script>

  where [path] is the path to this file on your server.

  Insert the following right after the <body>-tag:

    <script type="text/javascript" language="JavaScript1.2">
      if (efa_fontSize) efa_fontSize.efaInit();
    </script>

  Finally, insert the following where you wish the links to change the
  text size to appear:

    <script type="text/javascript" language="JavaScript1.2">
      if (efa_fontSize) document.write(efa_fontSize.allLinks);
    </script>
*/

/*
  efa_increment = percentage by which each click increases/decreases size
  efa_bigger = array of properties for 'increase font size' link
  efa_reset = array of properties for 'reset font size' link
  efa_smaller = array of properties for 'decrease font size' link

  properties array format:
    ['before HTML',
     'inside HTML',
     'title text',
     'class text',
     'id text',
     'name text',
     'accesskey text',
     'onmouseover JavaScript',
     'onmouseout JavaScript',
     'on focus JavaScript',
     'after HTML'
     ]
*/

var efa_default = 100;                      //default text size as percentage of user default
var efa_increment = 10;                      //percentage to increase/decrease font size

var efa_bigger = ['\n<ol id=\"schriftswitcher\">\n<li>', //HTML to go before 'bigger' link
          '<img src=\"http://www.bigge-energie.de/img/a_plus.png\" width=\"12\" height=\"12\" alt=\"gro&#223;e Schrift\" />',        //HTML to go inside 'bigger' anchor tag
          'Schriftgrad vergr&#246;&#223;ern',        //title attribute
          '',                      //class attribute
          '',                      //id attribute
          '',                      //name attribute
          '',                      //accesskey attribute
          '',                      //onmouseover attribute
          '',                      //onmouseout attribute
          '',                      //onfocus attribute
          '</li>'                      //HTML to go after 'bigger' link
          ]

var efa_reset = ['\n<li>',
         '<img src=\"http://www.bigge-energie.de/img/a_normal.png\" width=\"12\" height=\"12\" alt=\"normale Schrift\" />',        //HTML to go before 'reset' link
         'Schriftgrad normal',  //HTML to go inside 'reset' anchor tag
          '',                      //class attribute
          '',                      //id attribute
          '',                      //name attribute
          '',                      //accesskey attribute
          '',                      //onmouseover attribute
          '',                      //onmouseout attribute
          '',                      //onfocus attribute
          '</li>'                      //HTML to go after 'reset' link
          ]

var efa_smaller = ['\n<li>',
           '<img src=\"http://www.bigge-energie.de/img/a_minus.png\" width=\"12\" height=\"12\" alt=\"kleine Schrift\" />',        //HTML to go before 'smaller' link
           'Schriftgrad verkleinern',              //HTML to go inside 'smaller' anchor tag
           '',                      //class attribute
           '',                      //id attribute
           '',                      //name attribute
           '',                      //accesskey attribute
           '',                      //onmouseover attribute
           '',                      //onmouseout attribute
           '',                      //onfocus attribute
           '</li>\n</ol>'                  //HTML to go after 'smaller' link
           ]

function Efa_Fontsize(increment,bigger,reset,smaller,def) {
  // check for the W3C DOM
  this.w3c = (document.getElementById);
  // check for the MS DOM
  this.ms = (document.all);
  // get the userAgent string and normalize case
  this.userAgent = navigator.userAgent.toLowerCase();
  // check for Opera and that the version is 7 or higher; note that because of Opera's spoofing we need to
  // resort to some fancy string trickery to extract the version from the userAgent string rather than
  // just using appVersion
  this.isOldOp = ((this.userAgent.indexOf('opera') != -1)&&(parseFloat(this.userAgent.substr(this.userAgent.indexOf('opera')+5)) <= 7));
  // check for Mac IE; this has been commented out because there is a simple fix for Mac IE's 'no resizing
  // text in table cells' bug--namely, make sure there is at least one tag (a <p>, <span>, <div>, whatever)
  // containing any content in the table cell; that is, use <td><p>text</p></td> or <th><span>text</span></th>
  // instead of <td>text</td> or <th>text</th>; if you'd prefer not to use the workaround, then uncomment
  // the following line:
  // this.isMacIE = ((this.userAgent.indexOf('msie') != -1) && (this.userAgent.indexOf('mac') != -1) && (this.userAgent.indexOf('opera') == -1));
  // check whether the W3C DOM or the MS DOM is present and that the browser isn't Mac IE (if above line is
  // uncommented) or an old version of Opera
  if ((this.w3c || this.ms) && !this.isOldOp && !this.isMacIE) {
    // set the name of the function so we can create event handlers later
    this.name = "efa_fontSize";
    // set the cookie name to get/save preferences
    this.cookieName = 'efaSize';
    // set the increment value to the appropriate parameter
    this.increment = increment;
    //default text size as percentage of user default
    this.def = def;
    //intended default text size in pixels as a percentage of the assumed 12px
    this.defPx = Math.round(12*(def/100))
    //base multiplier to correct for small user defaults
    this.base = 1;
    // call the getPrefs function to get preferences saved as a cookie, if any
    this.pref = this.getPref();
    // stuff the HTML for the test <div> into the testHTML property
    this.testHTML = '<div id="efaTest" style="position:absolute;visibility:hidden;line-height:1em;">&nbsp;</div>';
    // get the HTML for the 'bigger' link
    this.biggerLink = this.getLinkHtml(1,bigger);
    // get the HTML for the 'reset' link
    this.resetLink = this.getLinkHtml(0,reset);
    // get the HTML for the 'smaller' link
    this.smallerLink = this.getLinkHtml(-1,smaller);
    // set up an onlunload handler to save the user's font size preferences
  } else {
    // set the link html properties to an empty string so the links don't show up
    // in unsupported browsers
    this.biggerLink = '';
    this.resetLink = '';
    this.smallerLink = '';
    // set the efaInit method to a function that only returns true so
    //we don't get errors in unsupported browsers
    this.efaInit = new Function('return true;');
  }
  // concatenate the individual links into a single property to write all the HTML
  // for them in one shot
  this.allLinks = this.biggerLink + this.resetLink + this.smallerLink;
}



// check the user's current base text size and adjust as necessary
Efa_Fontsize.prototype.efaInit = function() {
    // write the test <div> into the document
    document.writeln(this.testHTML);
    // get a reference to the body tag
    this.body = (this.w3c)?document.getElementsByTagName('body')[0].style:document.all.tags('body')[0].style;
    // get a reference to the test element
    this.efaTest = (this.w3c)?document.getElementById('efaTest'):document.all['efaTest'];
    // get the height of the test element
    var h = (this.efaTest.clientHeight)?parseInt(this.efaTest.clientHeight):(this.efaTest.offsetHeight)?parseInt(this.efaTest.offsetHeight):999;
    // check that the current base size is at least as large as the browser default (16px) adjusted
    // by our base percentage; if not, divide 16 by the base size and multiply our base multiplier
    //  by the result to compensate
    if (h < this.defPx) this.base = this.defPx/h;
    // now we set the body font size to the appropriate percentage so the user gets the
    // font size they selected or our default if they haven't chosen one
    this.body.fontSize = Math.round(this.pref*this.base) + '%';
    
}



// construct the HTML for the links; we expect -1, 1 or 0 for the direction, an array
// of properties to add to the <a> tag and HTML to go before, after and inside the tag
Efa_Fontsize.prototype.getLinkHtml = function(direction,properties) {
  // declare the HTML variable and add the HTML to go before the link, the start of the link
  // and the onclick handler; we insert the direction argument as a parameter passed to the
  // setSize method of this object
  var html = properties[0] + '<a href="#" onclick="efa_fontSize.setSize(' + direction + '); return false;"';
  // concatenate the title attribute and value
  html += (properties[2])?'title="' + properties[2] + '"':'';
  // concatenate the class attribute and value
  html += (properties[3])?'class="' + properties[3] + '"':'';
  // concatenate the id attribute and value
  html += (properties[4])?'id="' + properties[4] + '"':'';
  // concatenate the name attribute and value
  html += (properties[5])?'name="' + properties[5] + '"':'';
  // concatenate the accesskey attribute and value
  html += (properties[6])?'accesskey="' + properties[6] + '"':'';
  // concatenate the onmouseover attribute and value
  html += (properties[7])?'onmouseover="' + properties[7] + '"':'';
  // concatenate the onmouseout attribute and value
  html += (properties[8])?'onmouseout="' + properties[8] + '"':'';
  // concatenate the title onfocus and value
  html += (properties[9])?'onfocus="' + properties[9] + '"':'';
  // concatenate the link contents, closing tag and any HTML to go after the link and return the
  // entire string
  return html += '>'+ properties[1] + '<' + '/a>' + properties[10];
}



// get the saved preferences out of the cookie, if any
Efa_Fontsize.prototype.getPref = function() {
  // get the value of the cookie for this object
  var pref = this.getCookie(this.cookieName);
  // if there was a cookie value return it as a number
  if (pref) return parseInt(pref);
  // if no cookie value, return the default
  else return this.def;
}



// change the text size; expects a direction parameter of 1 (increase size), -1 (decrease size)
// or 0 (reset to default)
Efa_Fontsize.prototype.setSize = function(direction) {
  // see if we were passed a nonzero direction parameter;
  // if so, multiply it by the increment and add it to the current percentage size;
  // if the direction was negative, it will reduce the size; if the direction was positive,
  // it will increase the size; if the direction parameter is undefined or zero, reset
  // current percentage to the default
  this.pref = (direction)?this.pref+(direction*this.increment):this.def;
  this.setCookie(this.cookieName,this.pref);
  // set the text size
  this.body.fontSize = Math.round(this.pref*this.base) + '%';
}



// get the value of the cookie with the name equal to a string passed as an argument
Efa_Fontsize.prototype.getCookie = function(cookieName) {
  var cookie = cookieManager.getCookie(cookieName);
  return (cookie)?cookie:false;
}



// set a cookie with a supplied name and value
Efa_Fontsize.prototype.setCookie = function(cookieName,cookieValue) {
  return cookieManager.setCookie(cookieName,cookieValue);
}



var  efa_fontSize = new Efa_Fontsize(efa_increment,efa_bigger,efa_reset,efa_smaller,efa_default);