/home/mip/public_html_/old-website/ajax_captcha.js
/*
This is the JavaScript file for the How to Create CAPTCHA Protection using PHP and AJAX Tutorial
You may use this code in your own projects as long as this
copyright is left in place. All code is provided AS-IS.
This code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
For the rest of the code visit http://www.WebCheatSheet.com
Copyright 2006 WebCheatSheet.com
*/
//Gets the browser specific XmlHttpRequest Object
function getXmlHttpRequestObject() {
if (window.XMLHttpRequest) {
return new XMLHttpRequest(); //Mozilla, Safari ...
} else if (window.ActiveXObject) {
return new ActiveXObject("Microsoft.XMLHTTP"); //IE
} else {
//Display our error message
alert("Your browser doesn't support the XmlHttpRequest object.");
}
}
//Our XmlHttpRequest object
var receiveReq = getXmlHttpRequestObject();
//Initiate the AJAX request
function makeRequest(url, param) {
//If our readystate is either not started or finished, initiate a new request
if (receiveReq.readyState == 4 || receiveReq.readyState == 0) {
//Set up the connection to captcha_test.html. True sets the request to asyncronous(default)
receiveReq.open("POST", url, true);
//Set the function that will be called when the XmlHttpRequest objects state changes
receiveReq.onreadystatechange = updatePage;
receiveReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
receiveReq.setRequestHeader("Content-length", param.length);
receiveReq.setRequestHeader("Connection", "close");
//Make the request
receiveReq.send(param);
}
}
//Called every time our XmlHttpRequest objects state changes
function updatePage() {
//Check if our response is ready
if (receiveReq.readyState == 4) {
//Set the content of the DIV element with the response text
document.getElementById('result').innerHTML = receiveReq.responseText;
//Get a reference to CAPTCHA image
document.getElementById('capcha').style.display ="none";
img = document.getElementById('imgCaptcha');
//Change the image
img.src = 'create_image.php?' + Math.random();
}
}
//Called every time when form is perfomed
function getParam(theForm) {
//Set the URL
var url = 'captcha.php';
//Set up the parameters of our AJAX call
var postStr = theForm.txtCaptcha.name + "=" + encodeURIComponent( theForm.txtCaptcha.value );
//Call the function that initiate the AJAX request
makeRequest(url, postStr);
}