function InitAjax()
{
	alert("aqui!");
	var xmlHttp;

	// Firefox, Opera 8.0+, Safari
	try {   xmlHttp=new XMLHttpRequest(); }
	
	// Internet Explorer
	catch (e) 
	{
			      
		try {  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");   }
		catch (e)
		{
			try { xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); }
		   	catch (e)
      			{
			      alert("Your browser does not support AJAX!");
			      return false;
		     	}
		}
	}
	xmlHttp.onreadystatechange = function()
	{
		if (xmlHttp.readyState == 4) Populate(xmlHttp.responseText);
	}

	xmlHttp.open("POST", "pop_subjects.php", true);
	xmlHttp.send("pop_subjects.php");
}

function Populate(text)
{
	var ddl = document.getElementById('ddlSubjects');
	var subjects = eval('(' + text + ')');

	for (i in subjects)
	{
		var opt = document.createElement('option');
		opt.value = i;
		opt.text = subjects[i];
  		try { ddl.add(opt, null); }   // standards compliant
		catch(ex)  {    ddl.add(opt); }  // IE only
	}

}