$(function(){

  var s="abc <abc@gmail.com>, def <def23@gmail.com>";

  var sa= s.split(',');

  $.each(sa,function(i,item){

    //console.log(item);

    var start=item.indexOf("<");

    var end=item.indexOf(">");

    var email= item.substring(start+1,end);

    console.log(email);

  });

});