Using Javascript to fill a simple text-box captcha

[blackw...@gmail.com]

Hi guys! I'm a total noob, guys. Please help, I'm going to be filling that form for the next few years every month probably. Below the captcha I have to fill

Captcha:

<div class="form-inputs" style="font-size: 15px;">
            <p style="font-size: 15px;">* Equation: <span id="captcha-operation" style="font-size: 15px;">3+5</span> equals:
                <input data-contrast="placeholder" id="captcha-input" name="captcha" maxlength="2" onkeyup="this.value = this.value.replace(/\D/g, '')" style="" aria-required="true" aria-invalid="true" class="error" aria-describedby="captcha-input-error"><div id="captcha-input-error" class="error-cloud" style="display: block;">Check your answer</div>
            </p>
        </div>

 

Could anybody help me out what javascript code I'm supposed to use here? 

[blackw...@gmail.com]

Don't think I didn't try.

This is as far as I got:

var captchaAnswer = document.getElementById('captcha-operation');
document.getElementById('captcha-input').textContent = captchaAnswer;

No error in console, but no effect either.

BTW, if you want to try yourself here you have the original link. It's a polish, official receipt contest... lol

[blackw...@gmail.com]

GUYS GUYS I DID IT I HACK PENTAGON NOW OMG,

var captchaAnswer = document.getElementById('captcha-operation').innerHTML;

var real = eval(captchaAnswer);

document.getElementById('captcha-input').value = real;

for curious 

[madhuv...@gmail.com]

hi sir
iwant to auto fill captcha java script for this url: https://onlinebooking.sand.telangana.gov.in/Masters/Home.aspx
user id:8186049742
paassword:9553500248