How to hide the option in dropdown,which has been selected in the previous

Question

I have 4 dropdowns,in which i am populating the city names.For ex: Delhi,Mumbai,Bangalore.
Suppose if i select Delhi in first dropdown,it should not displayed in rest of 3 drop downs.How i have to solve this in jsp.
Thanks

Answer 1

here is a better code
public class dropdownex extends javax.swing.JFrame {
String[] list = { "Item 1", "Item 2", "Item 3", "Item 4"};
String[] master = { "Item 1", "Item 2", "Item 3", "Item 4"};
    /** Creates new form dropdownex */
    public dropdownex() {
        initComponents();
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                         
    private void initComponents() {
        jComboBox1 = new javax.swing.JComboBox();
        jComboBox2 = new javax.swing.JComboBox();
        jComboBox3 = new javax.swing.JComboBox();
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        getContentPane().setLayout(new java.awt.GridLayout());
        jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
        jComboBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox1ActionPerformed(evt);
        getContentPane().add(jComboBox1);
        jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
        jComboBox2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox2ActionPerformed(evt);
        getContentPane().add(jComboBox2);
        jComboBox3.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
        getContentPane().add(jComboBox3);
        pack();
    }// </editor-fold>                       
    private void jComboBox2ActionPerformed(java.awt.event.ActionEvent evt) {                                          
        // TODO add your handling code here:
        list[jComboBox2.getSelectedIndex()]=null;
        jComboBox3.setModel(new javax.swing.DefaultComboBoxModel(list));
    private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {                                          
        // TODO add your handling code here:
        list[0] = master[0];
        list[1] = master[1];
        list[2] = master[2];
        list[3] = master[3];
        list[jComboBox1.getSelectedIndex()]=null;
        jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(list));
        jComboBox3.setModel(new javax.swing.DefaultComboBoxModel(list));
    * @param args the command line arguments
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new dropdownex().setVisible(true);
    // Variables declaration - do not modify                    
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JComboBox jComboBox2;
    private javax.swing.JComboBox jComboBox3;
    // End of variables declaration                  
}