覆盖托管的Javascript函数

Question

I'm relatively new to javascript.

I'm currently trying to figure out how to override a javascript function from a hosted JS.

Background:

We won't be able to accept Amex card payment (Bank Issue). However, our embedded donation form still detects Amex cards when the card number is inserted.

Using Chrome, found this function, that I'm guessing is used to auto-detect card types. /

 function a(n) { var m = /^4/, i = /(^5[1-5])|^(222[1-8][0-9]{2}|2229[0-8][0-9]|22299[0-9]|22[3-9][0-9]{3}|2[3-6][0-9]{4}|27[01][0-9]{3}|2720[0-8][0-9]|27209[0-9])/, o = /^3[47]/, l = /^6(?:011|5|4[4-9]|22(?:1(?:2[6-9]|[3-9])|[2-8]|9(?:[01]|2[0-5])))/, h = /^(?:5[0678]|6304|6390|67)/, j = /^3(?:0[0-5]|[68][0-9])[0-9]/, k = /^(4026|417500|4405|4508|4844|4913|4917)/; if (k.test(n)) { return "electron" } else { if (m.test(n)) { return "visa" } else { if (i.test(n)) { return "mastercard" } else { if (o.test(n)) { return "amex" } else { if (l.test(n)) { return "discover" } else { if (h.test(n)) { return "maestro" } else { if (j.test(n)) { return "diners" } else { return "unknown" } } } } } } } } 

Will I be able to override the "o=/^3[47]/" to something else or remove it completely so Amex cards can't be detected, then insert in inside HTML?

Answer 1

Hello maybe a solution is to make your own if statement if amex is returned, so that you will set amex to unknown to.

var card = function a(n);
if(a === 'unknown' || a === 'amex'){
DoStuff();
}else{
DoRecognizedstuff();
}

This will help you solve the problem. Is this not what you want? You can also rewrite the function to this:

 function a(n) { var m = /^4/, i = /(^5[1-5])|^(222[1-8][0-9]{2}|2229[0-8][0-9]|22299[0-9]|22[3-9][0-9]{3}|2[3-6][0-9]{4}|27[01][0-9]{3}|2720[0-8][0-9]|27209[0-9])/, l = /^6(?:011|5|4[4-9]|22(?:1(?:2[6-9]|[3-9])|[2-8]|9(?:[01]|2[0-5])))/, h = /^(?:5[0678]|6304|6390|67)/, j = /^3(?:0[0-5]|[68][0-9])[0-9]/, k = /^(4026|417500|4405|4508|4844|4913|4917)/; if (k.test(n)) { return "electron" } else { if (m.test(n)) { return "visa" } else { if (i.test(n)) { return "mastercard" } else { if (l.test(n)) { return "discover" } else { if (h.test(n)) { return "maestro" } else { if (j.test(n)) { return "diners" } else { return "unknown" } } } } } } } 

This will only be possible if you call this function yourself. If it is called by a callback or something from the hosted JS it will not work. If this is a standalone script, you can just host the JS as your own.