var xmlHttp

function showTeachers(str)
{
if (str.length==0)
{ 
document.getElementById("teachers_div").innerHTML=""
return
}
document.getElementById("teachers_div").innerHTML="please wait ..."
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
{
alert ("Browser does not support HTTP Request,Please use Mozilla Firefox or Internet Explorer.")
return
}
var url="getteachers2.php"
url=url+"?q="+str
xmlHttp.onreadystatechange=stateChanged 
xmlHttp.open("GET",url,true)
xmlHttp.send(null)
} 

function stateChanged() 
{ 
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
{ 
document.getElementById("teachers_div").innerHTML=xmlHttp.responseText 
} 
} 

function GetXmlHttpObject()
{ 
var objXMLHttp=null
if (window.XMLHttpRequest)
{
objXMLHttp=new XMLHttpRequest()
}
else if (window.ActiveXObject)
{
objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")
}
return objXMLHttp
}