function getHTTPObject() { //from Bulletproof Ajax by Jeremy Keith
    var xhr = false;
    if (window.XMLHttpRequest) {
        xhr = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        try {
            xhr = new ActiveXObject("Msxml2.XMLHTTP");
        } catch(e) {
            try {
                xhr = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {
                xhr = false;
            }
        }
    }
    return xhr;
}

function readyContactForm(){
    document.getElementById("contactForm").onsubmit = function(){ //form name inside of getElementById
        var formData = "";
        for (var i=0; i < this.elements.length; i++){ //build post string
            if (i > 0){
                formData = formData + "&";
            }
            if (this.elements[i].type == "text" || this.elements[i].type == "textarea"){
                formData = formData + escape(this.elements[i].name) + "=" + escape(this.elements[i].value);
            }
            else if (this.elements[i].type == "select-one"){
                formData = formData + escape(this.elements[i].name) + "=" + this.elements[i].options[this.elements[i].selectedIndex].value;
            }
            else if (this.elements[i].type == "radio" || this.elements[i].type == "checkbox"){
                if (this.elements[i].checked){
                    formData = formData + escape(this.elements[i].name) + "=" + escape(this.elements[i].value);
                }
            }
        }
        var request = getHTTPObject();
        if (request){
            request.onreadystatechange = function (){
                if (request.readyState == 4 && (request.status == 200 || request.status == 304)){
                    document.getElementById("contactContainer").innerHTML = request.responseText; //container name inside of getElementById
                    readyContactForm(); //this function's name
                }
            };
            request.open("POST", "/contactForm.php", true); //second argument should be form logic/thank you content
            request.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            request.send(formData);
            return !true;
        }
        else {
            return !false;
        }
    }
}

readyContactForm(); //initialize ajax (above function name)