function getVisibleWidth() {
  if (self.innerWidth) return self.innerWidth;
  if (document.documentElement && document.documentElement.clientWidth) return document.documentElement.clientWidth;
  if (document.body) return document.body.clientWidth;
  return null;
}
function getVisibleHeight() {
  if (self.innerHeight) return self.innerHeight;
  if (document.documentElement && document.documentElement.clientHeight) return document.documentElement.clientHeight;
  if (document.body) return document.body.clientHeight;
  return null;
}

// ugly workaround for missing support for selectorText in Netscape6/Mozilla
// call onLoad() or before you need to do anything you would have otherwise used selectorText for.
var ugly_selectorText_workaround_flag = false;
var allStyleRules;
function ugly_selectorText_workaround() {
  if ((navigator.userAgent.indexOf("Gecko") == -1) || (ugly_selectorText_workaround_flag)) {
    return; // we've already been here or shouldn't be here
  }
  var styleElements = document.getElementsByTagName("style");

  for (var i = 0; i < styleElements.length; i++) {
    var styleText = styleElements[i].firstChild.data;
    // this should be using match(/\b[\w-.]+(?=\s*\{)/g but ?= causes an
    // error in IE5, so we include the open brace and then strip it
    allStyleRules = styleText.match(/\b[\w-.]+(\s*\{)/g);
  }

  for (var i = 0; i < allStyleRules.length; i++) {
    // probably insufficient for people who like random gobs of
    // whitespace in their styles
    allStyleRules[i] = allStyleRules[i].trim();
  }
  ugly_selectorText_workaround_flag = true;
}

// setStyleByNode: given an element node, style property and value, apply the style.
//  n - element node
//  p - property
//  v - value
function setStyleByNode(n, p, v) {
  n.style[p] = v;
}

// setStyleById: given an element id, style property and value, apply the style.
//  i - element id
//  p - property
//  v - value
function setStyleById(i, p, v) {
  var n = document.getElementById(i);
  setStyleByNode(n, p, v);
}

// getStyleByNode: given an element node and style property
// return the current setting for that property, or null.
// n - element node
// p - property
function getStyleByNode(n, p) {
  // try properties
  var s = eval("n." + p);
  if ((s != "") && (s != null)) return parse(s);

  // try inline
  var s = eval("n.style." + p);
  if ((s != "") && (s != null)) return parse(s);

  // try currentStyle
  if (n.currentStyle) {
    var s = eval("n.currentStyle." + p);
    if ((s != "") && (s != null)) return parse(s);
  }

  // try styleSheets
  var sheets = document.styleSheets;
  if (sheets.length > 0) {
    // loop over each sheet
    for (var x = 0; x < sheets.length; x++) {
      // grab stylesheet rules
      var rules = (sheets[x].cssRules) ? sheets[x].cssRules : sheets[x].rules;
      if (rules.length > 0) {
        // check each rule
        for (var y = 0; y < rules.length; y++) {
          var z = rules[y].style;
          // selectorText broken in NS 6/Mozilla: see http://bugzilla.mozilla.org/show_bug.cgi?id=51944
          ugly_selectorText_workaround();
          if (allStyleRules) {
            if (allStyleRules[y] == n) return parse(z[p]);
          }
          else {
            // use the native selectorText and style stuff
            if (((z[p] != "") && (z[p] != null)) || (rules[y].selectorText == n)) return parse(z[p]);
          }
        }
      }
    }
  }
  return null;
}

// getStyleById: given an element ID and style property return the current setting for that property, or null.
//  i - element id
//  p - property
function getStyleById(i, p) {
  var n = document.getElementById(i);
  return getStyleByNode(n, p);
}

// setStyleByClass: given an element type and a class selector, style property and value, apply the style.
//  t - type of tag to check for (e.g., SPAN)
//  c - class name
//  p - CSS property
//  v - value
function setStyleByClass(t,c,p,v){
  var elements;
  if (t == '*') {
    // '*' not supported by IE/Win 5.5 and below
    //var ie = (document.all) ? true : false;
    elements = (!!document.all) ? document.all : document.getElementsByTagName('*');
  }
  else {
    elements = document.getElementsByTagName(t);
  }
  for (var i = 0; i < elements.length; i++){
    var node = elements.item(i);
    for (var j = 0; j < node.attributes.length; j++) {
      if (node.attributes.item(j).nodeName == 'class') {
        if (node.attributes.item(j).nodeValue == c) eval('node.style.' + p + " = '" + v + "'");
      }
    }
  }
}

// getStyleByClass: given an element type, a class selector and a property, return the value of the property for that element type.
//  t - element type
//  c - class identifier
//  p - CSS property
function getStyleByClass(t, c, p) {
  // first loop over elements, because if they've been modified they will contain style data more recent than that in the stylesheet
  var elements;
  if (t == '*') {
    // '*' not supported by IE/Win 5.5 and below
    elements = (!!document.all) ? document.all : doc.getElementsByTagName('*');
  }
  else {
    elements = document.getElementsByTagName(t);
  }
  for (var i = 0; i < elements.length; i++){
    var node = elements.item(i);
    for (var j = 0; j < node.attributes.length; j++) {
      if (node.attributes.item(j).nodeName == 'class') {
        if (!!node.attributes.item(j).nodevalue) {
          var nv = node.attributes.item(j).nodevalue.split(',');
          for (var x = 0; x < nv.length; x++) {
            nvx = nv[x].trim();
            if (nvx == c || nvx == ("." + c) || nvx == (t + "." + c)) {
              var theStyle = eval('node.style.' + p);
              if ((theStyle != "") && (theStyle != null)) return theStyle;
            }
          }
        }
      }
    }
  }
  // if we got here it's because we didn't find anything yet
  // try styleSheets
  var sheets = document.styleSheets;
  if (sheets.length > 0) {
    // loop over each sheet
    for (var x = 0; x < sheets.length; x++) {
      // grab stylesheet rules
      var rules = (sheets[x].cssRules) ? sheets[x].cssRules : sheets[x].rules;
      if (rules.length > 0) {
        // check each rule
        for (var y = 0; y < rules.length; y++) {
          var z = rules[y].style;
          // selectorText broken in NS 6/Mozilla: see http://bugzilla.mozilla.org/show_bug.cgi?id=51944
          ugly_selectorText_workaround();
          if (allStyleRules) {
            if ((allStyleRules[y] == c) || (allStyleRules[y] == (t + "." + c))) return z[p];
          }
          else {
            // use the native selectorText and style stuff
            if ((z[p] != "") && (z[p] != null)) {
              var nv = rules[y].selectorText.split(',');
              for (var w = 0; w < nv.length; w++) {
                nvw = nv[w].trim();
                if (nvw == c || nvw == ("." + c) || nvw == (t + "." + c)) return z[p];
              }
            }
          }
        }
      }
    }
  }
  return null;
}

// setStyleByTag: given an element type, style property and value, and whether the property should override inline styles or
// just global stylesheet preferences, apply the style.
//  e - element type or id
//  p - property
//  v - value
//  g - boolean 0: modify global only; 1: modify all elements in document
function setStyleByTag(e, p, v, g) {
  if (g) {
    var elements = document.getElementsByTagName(e);
    for (var i = 0; i < elements.length; i++) elements.item(i).style[p] = v;
  }
  else {
    var sheets = document.styleSheets;
    if (sheets.length > 0) {
      for (var i = 0; i < sheets.length; i++) {
        var rules = (sheets[i].cssRules) ? sheets[i].cssRules : sheets[i].rules;
        if (rules.length > 0) {
          for (var j = 0; j < rules.length; j++) {
            var s = rules[j].style;
            // selectorText broken in NS 6/Mozilla: see http://bugzilla.mozilla.org/show_bug.cgi?id=51944
            ugly_selectorText_workaround();
            if (allStyleRules) {
              if (allStyleRules[j] == e) s[p] = v;
            }
            else {
              // use the native selectorText and style stuff
              if (((s[p] != "") && (s[p] != null)) && (rules[j].selectorText == e)) s[p] = v;
            }
          }
        }
      }
    }
  }
}

// getStyleByTag: given an element type and style property, return the property's value
//  e - element type
//  p - property
function getStyleByTag(e, p) {
  var sheets = document.styleSheets;
  if (sheets.length > 0) {
    for (var i = 0; i < sheets.length; i++) {
      var rules = (sheets[i].cssRules) ? sheets[i].cssRules : sheets[i].rules;
      if (rules.length > 0) {
        for (var j = 0; j < rules.length; j++) {
          var s = rules[j].style;
          // selectorText broken in NS 6/Mozilla: see http://bugzilla.mozilla.org/show_bug.cgi?id=51944
          ugly_selectorText_workaround();
          if (allStyleRules) {
            if (allStyleRules[j] == e) return s[p];
          }
          else {
            // use the native selectorText and style stuff
            if (((s[p] != "") && (s[p] != null)) && (rules[j].selectorText == e)) return s[p];
          }
        }
      }
    }
  }
  // if we don't find any style sheets, return the value for the first element of this type we encounter without a CLASS or STYLE attribute
  var elements = document.getElementsByTagName(e);
  var sawClassOrStyleAttribute = false;
  for (var i = 0; i < elements.length; i++) {
    var node = elements.item(i);
    for (var j = 0; j < node.attributes.length; j++) {
      if ((node.attributes.item(j).nodeName == 'class') || (node.attributes.item(j).nodeName == 'style')) sawClassOrStyleAttribute = true;
    }
    if (! sawClassOrStyleAttribute) return elements.item(i).style[p];
  }
}

// parse: to return eg 62 instead of 62px
function parse(r) {
  var parsed = parseFloat(r);
  return (isNaN(parsed)) ? r : parsed;
}