$(document).ready(function() {

    $("#button1").click( function() {
        alert("The selected value is: " + $("#dropdown1").val() ); 
        //or: 
        //alert("The selected value is: " + $("#dropdown1 :selected").text() ); 
    });

    $("#button2").click( function() {
        alert("The selected value is: " + $("#dropdown1 option[value="+$("#dropdown1").val()+"]").html() ); 
    });

    $("#button3").click( function() {
        $("#dropdown2").val("oranges");
    });

    $("#button4").click( function() {
        $("#dropdown2").val("bananas");
    });

    $("#button5").click( function() {
        $("#dropdown3").append('<option selected=selected value="grapes">20 Grapes</option>');
    });

    $("#button6").click( function() {
        $("#dropdown3").prepend('<option selected=selected value="melons">20 Melons</option>');
    });

    $("#button7").click( function() {
        $("#dropdown4 option[value='apples']").remove();
    });

    $("#button8").click( function() {
        $("#dropdown5 option[value='oranges']").attr("disabled", "disabled");
    });

    $("#button9").click( function() {
        $("#dropdown5 option[value='oranges']").removeAttr("disabled");
    });
});