// ==UserScript==
// @name Refresh Captcha On Mouse Click
// @match http://www.iichan.hk/*/res/*
// @match http://iichan.hk/*/res/*
// ==/UserScript==

var foo = document.evaluate("//input[@name='captcha']", document, null, XPathResult.ANY_TYPE, null);
var captchaText = foo.iterateNext();
var captchaImg = captchaText.nextElementSibling;
var imgSrc = captchaImg.getAttribute("src");
var dummyValueStart = imgSrc.indexOf("dummy=") + "dummy=".length;
var permanentPartOfCaptchaUrl = imgSrc.substring(0, dummyValueStart);
captchaImg.addEventListener("click", refreshCaptcha, false);

function refreshCaptcha(){
    var newDummy = Math.floor(Math.random() * 10000000);
    captchaImg.setAttribute("src", permanentPartOfCaptchaUrl + newDummy);
}

/*
  document.getElementsByName('captcha')[0].addEventListener('click', function() {
	var img = this.nextElementSibling;
	img.src = img.src.replace(/dummy=[\d\.]-asterisk-here-/, 'dummy=' + Math.random());
}, false);
*/