AJAX wil niet meewerken (Opgelost)

<script language="javascript">

var ajax

function get_suggestion(input)
{
	
	ajax = ajaxRequest();

	if( ajax == null )
	{
		alert('Je browser ondersteund geen ajax...');
		return;
	}

	xmlHttp.onreadystatechange = suggestie;
	xmlHttp.open("GET","suggestion.php?woord=" + input,true);
	xmlHttp.send(null);
}

function suggestie() 
{
	if (xmlHttp.readyState==4)
	{
		document.getElementById('box').innerHTML = xmlHttp.responseText;
	}

}

function ajaxRequest(){
	var ajax = null;
	try
	{
	
		ajax = new XMLHttpRequest();
		
	}
	catch(e)
	{
		try
		{
			ajax = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch(e)
		{
		
			ajax = new ActiveXObject("Microsoft.XMLHTTP");
		
		}
	}
	
	return ajax;
}

</script>

<script language="javascript">
 
var ajax
 
function get_suggestion(input)
{
 
	ajax = ajaxRequest();
 
	if( ajax == null )
	{
		alert('Je browser ondersteund geen ajax...');
		return;
	}
 
	xmlHttp.onreadystatechange = suggestie;
	xmlHttp.open("GET","suggestion.php?woord=" + input,true);
	xmlHttp.send(null);
}
 
function suggestie() 
{
	if (xmlHttp.readyState==4)
	{
		document.getElementById('box').innerHTML = xmlHttp.responseText;
	}
 
}
 
function ajaxRequest(){
	var ajax = null;
	try
	{
 
		ajax = new XMLHttpRequest();
 
	}
	catch(e)
	{
		try
		{
			ajax = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch(e)
		{
 
			ajax = new ActiveXObject("Microsoft.XMLHTTP");
 
		}
	}
 
	return ajax;
}
 
</script>

<form name="diablo">
	
    <input style="width:150px;" type="text" id="search" onkeyup="get_suggestion(this.value)" />
    <div id="box" style="background-color:#CCCCCC;width:150px;height:50px;overflow:auto"></div>
</form>

<form name="diablo">
 
    <input style="width:150px;" type="text" id="search" onkeyup="get_suggestion(this.value)" />
    <div id="box" style="background-color:#CCCCCC;width:150px;height:50px;overflow:auto"></div>
</form>