var encrypt_it=true;

function isCreditCard(st){
if(st.length>19)
return(false);sum=0;mul=1;l=st.length;for(i=0;i<l;i++){digit=st.substring(l-i-1,l-i);tproduct=parseInt(digit,10)*mul;if(tproduct>=10)
sum+=(tproduct%10)+1;else
sum+=tproduct;if(mul==1)
mul++;else
mul--;}if((sum%10)==0)
return(true);else
return(false);}function getCCNum(default_val){msg='Please enter your credit card number here.'
+'It will be'
+((encrypt_it)?" encrypted and then" :"")
+' put into the credit card field of the form'
+' after it is validated. Encrypted for security.';
return prompt(msg,default_val);}



function encrypt(val){val="" +val;var result="";for(i=0;i<val.length;i++){character=val.charAt(i);if("0123456789".indexOf(character)!=-1){character=parseInt(character);character=(character+1)%10;}result+=character;}if(result!="")
result+="e";return result;}function unencrypt(val){val="" +val;for(n=0;n<9;n++)
val=encrypt(val);return(val.substring(0,val.indexOf('e')));}function strip(val){val="" +val;if(!val)
return"";var result="";for(i=0;i<val.length;i++){character=val.charAt(i);if("0123456789".indexOf(character)!=-1)
result+=character;}return result;}var last_entry="";function doCCStuff(form_element){if(blur_reset){last_entry=form_element.value;if(last_entry&&last_entry.indexOf('e')!=-1)
last_entry=unencrypt(last_entry);entry=getCCNum(last_entry);stripped_entry=strip(entry);while(entry&&(!isCreditCard(stripped_entry))){alert('The credit card number you entered could not be'
+'validated.Please check the number and try again.');last_entry=entry;entry=getCCNum(last_entry);stripped_entry=strip(entry);}if(entry){if(encrypt_it)
form_element.value=encrypt(entry);else
form_element.value=entry;}blur_form(form_element);}return false;}var blur_reset=true;function blur_form(form_element){form_element.blur();blur_reset=false;setTimeout("blur_reset=true",2000);}