javascript servlet form textbox validation

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

//import javax.servlet.ServletContext;
//ServletContext myServletContext = getServletContext() ;

public class Encrypt extends HttpServlet
{
    private static final long serialVersionUID = 1L;

    protected void doGet( HttpServletRequest request, HttpServletResponse response )
      throws ServletException, IOException
    {
        String selfURL = request.getContextPath() + request.getServletPath();
        String userinput = request.getParameter( "userinput" );

        response.setContentType( "text/html" );     // MIME type
        PrintWriter responseout = response.getWriter();

        outputXHTMLHeader( "Servlet with Javascipt" , responseout );
        responseout.println( "<body>" );

        displaySubmitForm( "<div><input type=\"text\" name=\"userinput\" id=\"userinput\"/></div>" , selfURL , responseout );
        if( userinput != null && !userinput.isEmpty() )     // needs code injection protection
        {
            responseout.println( selfURL + " received input " + userinput + "<br />");
        }

        outputJavascript( responseout );
        responseout.println( "</body>" );
        responseout.println( "</html>" );
    } //end doGet

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException
    {
        doGet( request, response);
    }


    private static void outputJavascript( PrintWriter responseout )
    {
        responseout.println( "<script type=\"text/javascript\"> " );
        responseout.println( "<!--" );

    responseout.println( "function focusTextbox()" );
    responseout.println( "{" );
        responseout.println( "  var temp = document.getElementById( 'userinput' );" );
        responseout.println( "  temp.focus(); " );
        responseout.println( "}" );

        responseout.println( "function checkTextbox()" );
        responseout.println( "{" );
        responseout.println( "  var tempvalue = document.getElementById( 'userinput' ).value;" );
        responseout.println( "  alert( \"cleartext: \" + tempvalue );" );
        responseout.println( "}" );


        responseout.println( "focusTextbox();" );

        responseout.println( "//-->" );
        responseout.println( "</script>" );
    } //end outputJavascript

    private static void displaySubmitForm( String inputfield , String selfURL , PrintWriter responseout )
    {
        responseout.println( "<form name =\"submitbutton\" id=\"submitbutton\" action=\"" + selfURL + "\" method=\"post\" onsubmit=\"return checkTextbox()\" >" );
        responseout.println( inputfield );
        responseout.println( "<div><input type=\"submit\"/></div>" );
        responseout.println( "</form>" );
    } // end displaySubmitForm

    private static void outputXHTMLHeader( String title , PrintWriter responseout )
    {
        responseout.println( "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1//EN\" \"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd\">");
        responseout.println( "<html xmlns=\"http://www.w3.org/1999/xhtml\">" );
        responseout.println( "<head><title>" + title + "</title>" );
        responseout.println( "<meta http-equiv=\"Content-Type\" content=\"text/html;charset=utf-8\" />" );
        responseout.println( "</head>" );
    } //end outputXHTMLHeader

}//end class
javascript servlet form textbox validation

Published

Category

~212 words

Tags
