A large collection of jQuery operations on Select (collection)_jquery

1.jQuery adds/removes the Option item of Select:
2.$("#select_id").append("Text"); //Add an Option (drop-down item) to Select
3.$("#select_id").prepend("Please select< ;/option>"); //Insert an Option (first position) for Select
4.$("#select_id option:last").remove(); //Delete the Option with the largest index value in Select( The last one)
5.$("#select_id option[index='0']").remove(); //Delete the Option with index value 0 in Select (the first one)
6.$ ("#select_id option[value='3']").remove(); //Delete the Option with Value='3' in Select
7.$("#select_id option[text='4']" ).remove(); //Delete the Option with Text='4' in Select
8.$("#select_id").empty(); //Clear the option in select

1.jQuery gets the Text and Value selected by Select:
2.$("#select_id").change(function(){//code.. .}); //Add an event for Select, which is triggered when one of the items is selected
3.var checkText=$("#select_id").find("option:selected").text(); //Get Select's Text
4.var checkValue=$("#select_id").val(); //Get Select's Value
5.var checkIndex=$("#select_id ").get(0 ).selectedIndex; //Get the index value of Select
6.var maxIndex=$("#select_id option:last").attr("index"); //Get the maximum index value of Select jQuery sets Select selection Text and Value: