getElementsByClassName shims. Various shims solving this problem

getElementsByClassName.js

/*  
  All the getElementsByClassName functions below are in:
  http://snook.ca/archives/javascript/your_favourite_1 
*/
if( typeof document.getElementsByClassName !== "function"){
    document.getElementsByClassName= function( className, nodeName ){
        var a = [];
        var re = new RegExp('(^| )'+className+'( |$)');
        var els = nodeName.getElementsByTagName("*");
        for(var i=0,j=els.length; i<j; i++)
            if(re.test(els[i].className))a.push(els[i]);
        return a;
    };
}

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// The two functions below seem to be the most complete(cross browser) solution.
// document.all is equavallent to getElementsByTagName of IE 5
if( document.all && !document.getElementsByTagName ){
    document.getElementsByTagName = function( nodeName )
    {
        if( nodeName == '*' ) return document.all;
        var result = [], rightName = new RegExp( nodeName, 'i' ), i;
        for( i=0; i<document.all.length; i++ )
          if( rightName.test( document.all[i].nodeName ) )
        result.push( document.all[i] );
        return result;
    };
} // end if

// This if statement is my addition, the original code does not have it, it overrides the default function anyway
if( typeof document.getElementsByClassName !== "function"){ 
    document.getElementsByClassName = function( className, nodeName )
    {
      var result = [], tag = nodeName||'*', node, seek, i;
      if( document.evaluate ){
        seek = '//'+ tag +'[@class="'+ className +'"]';
        seek = document.evaluate( seek, document, null, 0, null );
        while( (node = seek.iterateNext()) )
          result.push( node );
      }else{
        var rightClass = new RegExp( '(^| )'+ className +'( |$)' );
        seek = document.getElementsByTagName( tag );
        for( i=0; i<seek.length; i++ )
          if( rightClass.test( (node = seek[i]).className ) )
        result.push( seek[i] );
      }
      return result;
    };
} // end if


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// This look good as well it uses document.querySelectorAll function which is IE8 specific
// and then for older versions of IE but not IE 5.x. Maybe by using the getElementsByTagName function
// above I sould be able to solve this problem.
if (!document.getElementsByClassName) {
  document.getElementsByClassName = function(search) {
    var d = document, elements, pattern, i, results = [];
    if (d.querySelectorAll) { // IE8
      return d.querySelectorAll("." + search);
    }
    if (d.evaluate) { // IE6, IE7
      pattern = ".//*[contains(concat(' ', @class, ' '), ' " + search + " ')]";
      elements = d.evaluate(pattern, d, null, 0, null);
      while ((i = elements.iterateNext())) {
        results.push(i);
      }
    } else {
      elements = d.getElementsByTagName("*");
      pattern = new RegExp("(^|\\s)" + search + "(\\s|$)");
      for (i = 0; i < elements.length; i++) {
        if ( pattern.test(elements[i].className) ) {
          results.push(elements[i]);
        }
      }
    }
    return results;
  };
}

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/* Also check this code at google: 
   https://code.google.com/p/getelementsbyclassname/source/browse/trunk/getElementsByClassName.js 
   However it looks complicated and cumbersome.
*/