$('span').each(function() {
var text = $(this).text();
if($(this).text().indexOf("-") + 1 == 1) {
(this).addClass('price-fall');
};
});
$('span').text((i, text) => text[0] === '-' ? text : `+${text}`);
document.querySelectorAll('span').forEach(n => {
n.innerText = n.innerText.replace(/^(?!-)/, '+');
});
for (const n of document.getElementsByTagName('span')) {
n.textContent = '+'.slice(n.textContent[0] === '-') + n.textContent;
}