Determine whether this element exists on the page of jquery. The jquery Element

Determine whether this element exists on the page of jquery. The jquery Element

When I was writing jquery, I sometimes used jq to determine whether an element exists on the page. At the beginning, I thought:

If ($ (obj). parent (). parent (). find ('. poa-list') = undefind) // determine whether the dd element exists

Or if ($ (obj). parent (). parent (). find ('. poa-list') // if this element exists

 

It is estimated that it was because of Javascript. For course, it was found that $ ("ddd") in jq was always true, and this element was always found, so it was changed to this one later.

 

If ($ (obj). parent (). parent (). find ('. poa-list'). length> 0)

In this way, you can determine whether or not it exists.