So I want to pass a variable like : childage_error1 childage_error2 childage_error3 etc. And I have this code right here:
for (var i = 0; i < gyermekek; i++) {
document.getElementById('gyermekkor_error' + (i + 1) + '').innerHTML = response.window['gyermekkor_error'+i+1]
}
If I put manually "gyermekkor_error1" it works but it wont work in a loop. It works in getElementById but not in the end.
response.window['gyermekkor_error'+i+1]
You are adding a string to a number plus a number. Basic order of operations left to right. The code does not assume you meant to add i to 1 first.
So you are getting
'gyermekkor_error01'
'gyermekkor_error11'
'gyermekkor_error21'
'gyermekkor_error31'
You need to surround the addition part with parenthesis
response.window['gyermekkor_error' + (i+1)]
Or just start your loop off at one so you do not need the addition step.
for (var i = 1; i <= gyermekek; i++) {
var key = 'gyermekkor_error' + i;
document.getElementById(key).innerHTML = response.window[key];
}