Open Chrome Developer Console, WIN Ctrl+Shift+J
or MAC Cmd+Opt+J
, paste and enter
function saveAllAmazonCartItemsForLater() {
var query = document.querySelectorAll("#activeCartViewForm input[value='Save for later']")
console.log('started');
if (query.length) {
console.log('query.length = ' + query.length);
query[0].click();