In such cases, you are better off re-adding the whitespace which makes the syntax error immediate apparent:
function(){
if(xmlhttp.readyState==4&&xmlhttp.status==200){
document.getElementById("content").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","data/"+id+".html",true);xmlhttp.send();
}
There's a } too many. Also, after the closing } of the function, you should add a ; before the xmlhttp.open()
And finally, I don't see what that anonymous function does up there. It's never executed or referenced. Are you sure you pasted the correct code?