redo this without using queryselector

function checkAnswer$($questionIndex$)\{$

var selectedAnswer $=$ null;

var radioButtons $=$ document.getElementsByName$(\text{'}$answer$-\text{'}+$ questionIndex$)$;

for $($var i $=0$; i $<$ radioButtons.length; i$++)\{$

if $($radioButtons$[$i$].$checked$)\{$

selectedAnswer $=$ radioButtons$[$i$]$;

break;

$\}$

$\}$

if $(!$selectedAnswer$)\{$

window.alert$(\text{'}$Please select an answer.$\text{'})$;

return;

$\}$

var correctAnswer $=$ document.getElementById$(\text{'}$correct$-$answer$-\text{'}+$ questionIndex$).$value;

if $($selectedAnswer$.$value $===$ correctAnswer$)\{$

selectedAnswer.parentElement.classList.add$(\text{'}$highlight$-$correct'$)$;

correctAnswerCount$++$; $//$ Increment correct answers count

$\}$ else $\{$

selectedAnswer.parentElement.classList.add$(\text{'}$highlight$-$incorrect'$)$;

var correctAnswerInput $=$ document.querySelector$(\text{'}$input$[$value$="\text{'}+$ correctAnswer $+\text{'}"]\text{'})$;

if $($correctAnswerInput$)\{$

correctAnswerInput.parentElement.classList.add$(\text{'}$highlight$-$correct'$)$;

$\}$

$\}$