how to judge an element's previous or next element exist with jquery?

Question

suppose I have an

:

Answer 1

if ($("li.test").next().length > 0) { ... }

http://jsfiddle.net/Kfsku/

Answer 2

You need to check the length property.

if ($("li.test").next().length) {
  //has next 
} else {
  //last elem
}

Keep in mind that jQuery usually returns itself so you can chain. Getting the length property of that object will give you the information

Answer 3

$("li.test").next().length;

Example

Answer 4

A jQuery selection will always evaluate to boolean true (as in an if statement). This is because it is not a native Javascript type -- it is an object.

You need to check the length property of the selection. If it is empty, this will be 0 and will evaluate to false, so the if will not pass. If it is not empty, it will be a positive integer and will therefore evaluate to true, so the conditional will pass.

if ($("li.test").next().length) { …… }