jQuery find next/prev elements of a certain class but not necessarily siblings

Question

The next, prev, nextAll and prevAll methods are very useful, but not if the elements you are trying to find are not in the same parent element. What I want to do is something like this:

<div>
    <span id="click">Hello</span>
</div>
<div>
    <p class="find">World></p>
</div>

When the span with the id click is pressed, I want to match the next element with the class find, which in this case is not a sibling of the clicked element so next() or nextAll() won't work.

Answer 1

Try this. It will mark your Element, create a set of Elements matching your selector and collect all Elements from the set following your element.

$.fn.findNext = function ( selector ) {
    var set = $( [] ), found = false;
    $( this ).attr( "findNext" , "true" );
    $( selector ).each( function( i , element ) {
        element = $( element );
        if ( found == true ) set = set.add( element )
        if ( element.attr("findNext") == "true" ) found = true;
    })
    $( this ).removeAttr( "findNext" )
    return set
}

EDIT

much simpler solution using jquerys index method. the element you call the method from needs to be selectable by the same selector though

$.fn.findNext = function( selector ){
    var set = $( selector );
    return set.eq( set.index( this, ) + 1 )
}

to free the function from this handicap, we could youse the browsers own compareDocumentposition

$.fn.findNext = function ( selector ) {
  // if the stack is empty, return the first found element
  if ( this.length < 1 ) return $( selector ).first();
  var found,
      that = this.get(0);
  $( selector )
    .each( function () {
       var pos = that.compareDocumentPosition( this );
       if ( pos === 4 || pos === 12 || pos === 20 ){
       // pos === 2 || 10 || 18 for previous elements 
         found = this; 
         return false;
       }    
    })
  // using pushStack, one can now go back to the previous elements like this
  // $("#someid").findNext("div").remove().end().attr("id")
  // will now return "someid" 
  return this.pushStack( [ found ] );
},  

EDIT 2 this is far easier using jQuery's $.grep. here's the new code

   $.fn.findNextAll = function( selector ){
      var that = this[ 0 ],
          selection = $( selector ).get();
      return this.pushStack(
         // if there are no elements in the original selection return everything
         !that && selection ||
         $.grep( selection, function( n ){
            return [4,12,20].indexOf( that.compareDocumentPosition( n ) ) > -1
         // if you are looking for previous elements it should be [2,10,18]
         })
      );
   }
   $.fn.findNext = function( selector ){
      return this.pushStack( this.findNextAll( selector ).first() );
   }

when compressing variable names this becomes a mere two liner.

Edit 3 using bitwise operations, this function may be even faster?

$.fn.findNextAll = function( selector ){
  var that = this[ 0 ],
    selection = $( selector ).get();
  return this.pushStack(
    !that && selection || $.grep( selection, function(n){
       return that.compareDocumentPosition(n) & (1<<2);
       // if you are looking for previous elements it should be & (1<<1);
    })
  );
}
$.fn.findNext = function( selector ){
  return this.pushStack( this.findNextAll( selector ).first() );
}