jQuery：如何找到前一个复选框被选中

Question

I have a code that each checking/unchecking the checkbox respectively adds/subtracts a certain amount. Everything works perfectly, but when the first checbox leave "checked" and I press to a second, then the first checbox I "unchecked", but the script didn't subtracts a certain amount. I want to create if, that can match previous checbox and present (it is different), and if it's different will take away a certain amount of this first. This is my if instruction ( lastClicked.find('input[type=checbox]').attr("checked") doesn't work)

if(!((lastClicked.length == $(this).length && lastClicked.length == lastClicked.filter($(this)).length) || lastClicked==="") && lastClicked.find('input[type=checbox]').attr("checked"))

And here is code: https://jsfiddle.net/3p5z6zov/

Answer 1

Use prop() instead of attr()

►If you're using jQuery 1.6 or later, use prop() instead of attr()

lastClicked.find('input[type=checbox]').prop("checked")

When you are using prop() , the value returned will be Boolean