So I want a form that is submitted with ajax. What I have so far works fine in IE but not in Firefox. Heres my code:

Code:
//Sends Sign-Up Form
function sendsuf(){
	var ajaxRequest;
	
	try{
		// Opera 8.0+, Firefox, Safari
		ajaxRequest = new XMLHttpRequest();
	} catch (e){
		// Internet Explorer Browsers
		try{
			ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try{
				ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e){
				// Something went wrong
				alert("Your browser broke!");
				return false;
			}
		}
	}
	// function that will receive data sent from the server
	ajaxRequest.onreadystatechange = function(){
		if(ajaxRequest.readyState == 4){
				alert(ajaxRequest.responseText);
		}
	}


//  I think the problem is somewhere below this line

	ajaxRequest.open('POST', 'adduser.php', true);
	ajaxRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	ajaxRequest.setRequestHeader("Content-length", params.length);
	ajaxRequest.setRequestHeader("Connection", "close");

    	var fullname = document.getElementById('fullname').value;
    	var email = document.getElementById('email').value;


	ajaxRequest.send('fullname=' + fullname + '&email=' + email);
}
Any ideas?

Thanks