let fieldId = 0;
let somethingIsSelected = false;

for(let i = 0; i < 64; i++){
    fieldId = i.toString();
    document.getElementById("field"+fieldId).selected = 0;
}
function selectField(field){
    console.log(field.id);
    for(let i = 0; i < 64; i++){
        fieldId = i.toString();
        if(document.getElementById("field"+fieldId).selected === 1){
            somethingIsSelected = true;
        }
    }
    if(!somethingIsSelected) {
        field.style.backgroundColor = "rgb(227,8,8, 0.3)";
        field.selected = 1;
    } else if (field.selected === 1){
        field.style.backgroundColor = "rgb(255,255,255, 1)";
        field.selected = 0;
        somethingIsSelected = false;
    }
}