Opening and Closing Windows Using JavaScript

How to open a page in new browser window and specify the features of that window.

About this technique	Details
Category	HTML Client Techniques> JavaScript
Description	You'll learn about: Getting user-specified window features Using openWindow(url, window, features) Using openWindow(url, window, features, params) Using openWindow(url, window, features, query, orderby) Applying request information to the page in the window Closing the window
	You can run this technique code from: Database: Examples3_HTML Page: pgWindowOpenClose.html NOTE   First make sure that database is running on your localhost SilverStream Server
Related reading	See the chapter on advanced page topics in the Programmer's Guide

This example uses the agScriptHelper utility object's various openWindow() methods. The agScriptHelper methods perform tasks that are similar to JavaScript functions, saving you from having to write JavaScript code directly (such as when you need to manipulate browser windows).

Getting user-specified window features   

The following code shows the features() method, which returns a string that specifies the features of the window to open. The string is used by AgpScriptHelper's openWindow() method.

The controls menubar, toolbar, resizable, status, and scrollbars are checkbox controls. The code uses getState() to determine if each checkbox is set or cleared. It uses the features variable to contain the concatenation of all checkbox states. The features() method returns the features variable, which specifies the type of window to open.

  public String features() 
  { 
     String features = "width=550,height=275"; 
      
     if (menubar.getState()) 
     { 
        features += ",menubar=yes"; 
     } 
     else 
     { 
        features += ",menubar=no"; 
     } 
     if (toolbar.getState()) 
     { 
        features += ",toolbar=yes"; 
     } 
     else 
     { 
        features += ",toolbar=no"; 
     } 
     if (resizable.getState()) 
     { 
        features += ",resizable=yes"; 
     } 
     else 
     { 
        features += ",resizable=no"; 
     } 
     if (status.getState()) 
     { 
        features += ",status=yes"; 
     } 
     else 
     { 
        features += ",status=no"; 
     } 
     if (scrollbars.getState()) 
     { 
        features += ",scrollbars=yes"; 
     } 
     else 
     { 
        features += ",scrollbars=no"; 
     } 
   
     return features; 
      
  } 

Notes about the code

• Declare and initialize the features variable to the string specifying the window's initial width and height.

• Determine if the user has selected the menu bar checkbox by calling menubar.getState(). This method returns true if the checkbox is selected.

• In this case, append the string ",menubar=yes" to the features variable to indicate that the window to open has a menu bar.

• If the menu bar checkbox is not selected, append the string ",menubar=no" instead to indicate that the window to open does not have a menu bar.

• Similarly, call getState() on the toolbar, resizable, status, and scroll bar objects to get the user-specified features for the window.

• Append the appropriate strings to indicate if the window:
  • Has a toolbar

  • Can be resized

  • Has a status bar

  • Has scroll bars

• Finally, return the resulting features string.

Using openWindow(url, window, features)   

The following code opens a window when the user clicks the first button (Button1). It calls the features() method to get the user specifications for the window's features. It then calls the 3-argument openWindow() method on the agScriptHelper object, which is an instance of the AgpScriptHelper class. This is a utility class that provides methods that create JavaScript code so that you can access certain JavaScript functionality without having to know JavaScript. This instantiation occurs automatically with each page.

  private void handle_Button1_pageActionPerformed(ActionEvent evt) throws Exception 
  { 
     String features = features(); 
     agScriptHelper.openWindow("pgWindowToBeOpened.html", "new", features); 
  } 

Notes about the code

• Get the window features that the user specifies by calling features().

• Create and open a window by calling openWindow() on agScriptHelper and specifying the following:
  • The page URL is pgWindowToBeOpened.html (located in the same directory as the page pgWindowOpenClose).

  • The destination window is not an existing one. Create a new window.

  • The features are in the string returned by the features() method.

Using openWindow(url, window, features, params)   

The following code opens a window when the user clicks the second button (Button2). It calls the 4-argument openWindow() method on the agScriptHelper object, which is an instance of the AgpScriptHelper class. The additional parameter is params, which is a Hashtable of parameters to send with the request to open the window. The displayed page (that is, the document that the client gets) will extract and use the parameters as appropriate.

  private void handle_Button2_pageActionPerformed(ActionEvent evt) throws Exception 
  { 
     String features = features(); 
      
     Hashtable params = new Hashtable(); 
     params.put("param1", "ONE"); 
     params.put("param2", "TWO"); 
     params.put("param3", "THREE"); 
      
     agScriptHelper.openWindow("pgWindowToBeOpened.html", "new", features, params); 
  } 

Notes about the code

• Create a Hashtable and enter three key-value data pairs in it.

• Open a new window with the supplied parameters, including the Hashtable of parameters.

Using openWindow(url, window, features, query, orderby)   

The following code opens a window when the user clicks the third button (Button3). It calls the 5-argument openWindow() method on the agScriptHelper object, which is an instance of the AgpScriptHelper class. The parameter query specifies the rows (of the data bound to the page) to display in the opened window. The parameter orderby specifies the display order of the rows. In this example, it is set to NULL.

  private void handle_Button3_pageActionPerformed(ActionEvent evt) throws Exception 
  { 
     String features = features(); 
     agScriptHelper.openWindow("pgWindowToBeOpened.html", "new", features, 
        "contacts.id > 0", null); 
  } 

Notes about the code

• When calling the openWindow() method, set the query parameter to "contacts.id > 0" to specify that the page in the new window displays rows of the contacts table whose id column values are greater than 0.

• Various text fields in the destination page are bound to specific columns in the contacts table.

Applying request information to the page in the window   

The following code shows the pageRequestBegin event on the page pgWindowToBeOpened. This code runs immediately after the page is first loaded and at the beginning of every subsequent page request. It attempts to get specific data from the servlet request and uses them appropriately.

For example, if the user clicked on the second button in the pgWindowOpenClose page, the 4-argument openWindow() method executes with a Hashtable as one of the parameters. The following method is able to get the Hashtable's values to display them in text fields. If, however, the user clicks the first button, the 3-argument openWindow() method executes, and there will be no Hashtable values to extract from the servlet request.

  //Method in pgWindowToBeOpened 
   
  protected void pageRequestBegin(AgiHttpServletRequest req, AgiHttpServletResponse res) throws Exception 
  { 
     String[] values = req.getParameterValues("param1"); 
     if (values != null) 
        Label1.setText(values[0]); 
     else 
        Label1.setText(""); 
      
     values = req.getParameterValues("param2"); 
     if (values != null) 
        Label2.setText(values[0]); 
     else 
        Label2.setText(""); 
      
     values = req.getParameterValues("param3"); 
     if (values != null) 
        Label3.setText(values[0]); 
     else 
        Label3.setText(""); 
   
     String queryString = req.getQueryString(); 
     System.out.println("QUERYSTRING = " + queryString); 
     if (queryString != null) 
     { 
        if (queryString.indexOf("query") >= 0) 
           agData.gotoFirst(); 
        else 
           agData.clearRows(); 
     } 
     else 
        agData.clearRows(); 
  } 

Notes about the code

• Get the param1 value from the servlet request by calling getParameterValues(), and assign it to the values string array.

• Set the display text of the Label1 label to that value.

• Similarly, get the values of the other parameters in the Hashtable and use them to set the text of corresponding labels.

• Get the query string that is part of the HTTP request by calling getQueryString() on the request object.

• Verify that the string "query" is a substring in the returned string by checking that indexOf() does not return -1.

• If so, position the cursor at the first row by calling agData.gotoFirst(); otherwise, clear the rows with agData.clearRows().

Closing the window   

The following code closes the window when the user clicks the Close window button in the pgWindowToBeOpened page.

  //Method in pgWindowToBeOpened 
   
  private void handle_close_pageActionPerformed(ActionEvent evt) throws Exception 
  { 
     agScriptHelper.closeWindow(); 
  } 

Notes about the code

• agScriptHelper is an AgpScriptHelper instance. This utility class generates JavaScript code.

• Call agScriptHelper.closeWindow() to close the current browser window.