Easy Captcha javascript script
***annuncioVideo***
A little soft easy and user-friendy captcha, instead of sometimes hard reading captcha we can view in some sites.
Captcha number is created by a javascript client-side script, and inserted in a hidden input field.
You can run a double check:
- client-side: check if random js number is the same value of hidden field
- server-side: checking fields url.captcha and url.captchaHidden
Test page : captcha.cfm (a standard HTML page, without server-side script).
Let check it 
<script language="javascript">
function myLayer (x){
//object finding
if(document.layers){ // browser="NN4";
lay=document.layers[x];
}
if(document.all){ // browser="IE";
lay=eval("document.all." + x);
}
if(!document.all && document.getElementById){ // browser="NN6+ or IE5+ if you’re willing to dump the !document.all stuff";
lay=document.getElementById(x);
}
return lay;
}
function fnCaptcha(){
var numero=Math.random()*7*666;
var numero=Math.floor(numero);
myLayer("captchaNumber").innerHTML = numero;
document.frmCaptcha.captchaHidden.value = numero;
}
function fnCaptchaCheck(f){
if ((f.captcha.value == "") || (f.captcha.value == f.captchaHidden.value)){
alert("Different numbers. Check KO ");
}else{
alert("Same numbers. Check OK. ");
}
return false();
}
window.onload=function(){fnCaptcha();}
</script>
<h3>Prova Captcha</h3>
Insert number you can see between brackets (<span id="captchaNumber"></span>)<br />
<form id="frmCaptcha" name="frmCaptcha" method="post" action="" onsubmit="return fnCaptchaCheck(this)">
<input name="captcha" type="text" id="captcha" />
<input name="captchaHidden" type="hidden" id="captchaHidden" />
<input type="button" name="Submit" value="Pulsante" />
</form>
<br />
To improve security level, you can translate form from get post, to form post.
Approfondimenti online
La tecnologia informatica ha fatto passi da gigante. In modo particolare Google, che con il suo analizzatore di testo, è in grado di proporre collegamenti contestuali a quanto hai appena letto. Questi i link pubblicitari proposti da Adsense.
(f.captcha.value == f.captchaHidden.value)
should be
(f.captcha.value !== f.captchaHidden.value)
or am I missing something?
@mauricio: please go to these new link:
- http://tinyurl.com/2bwcwg
- http://tinyurl.com/yphfkr
And
http://hiddy.etechs.it