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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="Author" content="Norris Boyd">
<meta name="GENERATOR" content="Mozilla/4.7 [en] (WinNT; I) [Netscape]">
<meta name="KeyWords" content="Rhino, JavaScript, Java, Debugger">
<title>Rhino Debugger</title>
</head>
<body bgcolor="#FFFFFF">
<script src="owner.js">
</script>
<center>
<h1>
Rhino JavaScript Debugger</h1></center>
Christopher Oliver
<br><script>document.write(owner());</script>
<br>6/28/2001
<center>
<hr WIDTH="100%"></center>
The Rhino JavaScript debugger is a GUI that allows debugging of interpreted
JavaScript scripts run in Rhino. Note that this debugger <i>will not</i>
work with JavaScript scripts run in the mozilla browser since Rhino is
not the engine used in such environments.
<p><img SRC="jsdebug.jpg" height=460 width=600>
<p>Current limitations:
<ul>
<li>
Requires JDK 1.2 or greater</li>
<li>
Requires js.jar from rhinoTip.zip</li>
<li>
No breakpoint menu</li>
</ul>
<b><font face="Arial"><font color="#000080"><font size=+2>Using the Rhino
JavaScript Debugger</font></font></font></b>
<p><font size=-1>The Mozilla Rhino JavaScript engine includes a source-level
debugger for debugging JavaScript scripts. The debugger is itself a Java
program which you may run as</font>
<ol><font face="Arial"><font size=-1>java org.mozilla.javascript.tools.debugger.Main
[options] [filename.js] [script-arguments]</font></font></ol>
<font size=-1>where the options are the same as the shell.</font>
<p><font size=-1>The Rhino JavaScript Debugger can debug scripts running
in multiple threads and provides facilities to set and clear breakpoints,
control execution, view variables, and evaluate arbitrary JavaScript code
in the current scope of an executing script.</font>
<p><a NAME="_Toc502165109"></a><b><font face="Arial"><font color="#000080"><font size=-1>Console
Window</font></font></font></b>
<br><font size=-1>The debugger redirects the <font face="Arial">System.out</font>,
<font face="Arial">System.in</font>,
and <font face="Arial">System.err</font> streams to an internal JavaScript
console window which provides an editable command line for you to enter
JavaScript code and view system output. The console window maintains a
history of the commands you have entered. You may move backward and forward
through the history list by pressing the Up/Down arrow keys on the keyboard.</font>
<br><a NAME="_Toc502165110"></a><b><font face="Arial"><font color="#000080"><font size=-1>Opening
Scripts</font></font></font></b>
<br><font size=-1>You may select the <b><i>File->Open</i></b> menu item
on the menu bar to load JavaScript scripts contained in files. This action
will display a file-selection dialog box prompting you for the location
of a script to load. The selected file will be compiled and displayed in
a new window.</font>
<br><a NAME="_RunningScripts"></a><b><font face="Arial"><font color="#000080"><font size=-1>Running
Scripts</font></font></font></b>
<br><font size=-1>You may select the <b><i>File->Run</i></b> menu item
on the menu bar to execute JavaScript scripts contained in files. This
action will display a file-selection dialog box prompting you for the location
of a script to execute. The loaded script will be run in a new thread and
control will be given to the debugger on its first instruction.</font>
<p><a NAME="_Toc502165111"></a><b><font face="Arial"><font color="#000080"><font size=+1>Controlling
Execution</font></font></font></b>
<br><font size=-1>The debugger provides the following facilities for you
to control the execution of scripts you are debugging:</font>
<p><b><font face="Arial"><font color="#000080">Step Into</font></font></b>
<br><font size=-1>To single step entering any function calls, you may do
any of the following:</font>
<ul>
<li>
<font size=-1>Select the <b><i>Debug->Step Into </i></b>menu item on the
menu bar</font></li>
<li>
<font size=-1>Press the <b><i>Step Into</i></b> button on the toolbar</font></li>
<li>
<font size=-1>Press the F11 key on the keyboard</font></li>
</ul>
<font size=-1>Execution will resume. If the current line in the script
contains a function call control will return to the debugger upon entry
into the function. Otherwise control will return to the debugger at the
next line in the current function.</font>
<p><b><font face="Arial"><font color="#000080">Step Over</font></font></b>
<br><font size=-1>To single step to the next line in the current function,
you may do any of the following:</font>
<ul>
<li>
<font size=-1>Select the <b><i>Debug->Step Over</i></b> menu item on the
menu bar</font></li>
<li>
<font size=-1>Press the <b><i>Step Over</i></b> button on the toolbar</font></li>
<li>
<font size=-1>Press the F7 key on the keyboard</font></li>
</ul>
<font size=-1>Execution will resume but control will return to the debugger
at the next line in the current function or top-level script.</font>
<p><b><font face="Arial"><font color="#000080">Step Out</font></font></b>
<br><font size=-1>To continue execution until the current function returns
you may do any of the following:</font>
<ul>
<li>
<font size=-1>Select the <b><i>Debug->Step Out</i></b> menu item on the
menu bar</font></li>
<li>
<font size=-1>Press the <b><i>Step Out</i></b> button on the toolbar</font></li>
<li>
<font size=-1>Press the F8 key on the keyboard</font></li>
</ul>
<font size=-1>Execution will resume until the current function returns
or a breakpoint is hit.</font>
<p><b><font face="Arial"><font color="#000080">Go</font></font></b>
<br><font size=-1>To resume execution of a script you may do any of the
following:</font>
<ul>
<li>
<font size=-1>Select the <b><i>Debug->Go</i></b> menu item on the menu
bar</font></li>
<li>
<font size=-1>Press the <b><i>Go</i></b> button on the toolbar</font></li>
<li>
<font size=-1>Press the F5 key on the keyboard</font></li>
</ul>
<font size=-1>Execution will resume until a breakpoint is hit or the script
completes.</font>
<p><b><font face="Arial"><font color="#000080">Break</font></font></b>
<br><font size=-1>To stop all running scripts and give control to the debugger
you may do any of the following:</font>
<ul>
<li>
<font size=-1>Select the <b><i>Debug->Break</i></b> menu item on the menu
bar</font></li>
<li>
<font size=-1>Press the <b><i>Break</i></b> button on the toolbar</font></li>
<li>
<font size=-1>Press the Pause/Break key on the keyboard</font></li>
</ul>
<a NAME="_RunningScripts"></a><b><font face="Arial"><font color="#000080"><font size=-1>Break
on Exceptions</font></font></font></b>
<br><font size=-1>To give control to the debugger whenever a JavaScript
is exception is thrown select the <b><i>Debug->Break on Exceptions</i></b>
checkbox from the menu bar.&nbsp; Whenever a JavaScript exception is thrown
by a script a message dialog will be displayed and control will be given
to the debugger at the location the exception is raised.</font>
<p><a NAME="_BreakOnFunctionEnter"></a><b><font face="Arial"><font color="#000080"><font size=-1>Break on Function Enter</font></font></font></b>
<br><font size=-1>Selecting <b><i>Debug->Break on Function Enter</i></b> will give control to the debugger whenever the execution is entered into a function or script.</font>
<p><a NAME="_BreakOnFunctionExit"></a><b><font face="Arial"><font color="#000080"><font size=-1>Break on Function Exit</font></font></font></b>
<br><font size=-1>Selecting <b><i>Debug->Break on Function Return</i></b> will give control to the debugger whenever the execution is about to return from a function or script.</font>
<p><a NAME="_Toc502165112"></a><b><font face="Arial"><font color="#000080">Moving
Up and Down the Stack</font></font></b>
<br><font size=-1>The lower-left (dockable) pane in the debugger main window
contains a combo-box labeled "Context:" which displays the current stack
of the executing script. You may move up and down the stack by selecting
an entry in the combo-box. When you select a stack frame the variables
and watch windows are updated to reflect the names and values of the variables
visible at that scope.</font>
<p><a NAME="_Toc502165113"></a><b><font face="Arial"><font color="#000080">Setting
and Clearing Breakpoints</font></font></b>
<br><font size=-1>The main desktop of the debugger contains file windows
which display the contents of each script you are debugging. You may set
a breakpoint in a script by doing one of the following:</font>
<ul>
<li>
<font size=-1>Place the cursor on the line at which you want to set a breakpoint
and right-click with the mouse. This action will display a pop-up menu.
Select the <b><i>Set Breakpoint</i></b> menu item.</font></li>
<li>
<font size=-1>Simply single-click on the line number of the line at which
you want to set a breakpoint.</font></li>
</ul>
<font size=-1>If the selected line contains executable code a red dot will
appear next to the line number and a breakpoint will be set at that location.</font>
<p><font size=-1>You may clear breakpoint in a script by doing one of the
following:</font>
<ul>
<li>
<font size=-1>Place the cursor on the line at which you want to clear a
breakpoint and right-click with the mouse. This action will display a pop-up
menu. Select the <b><i>Clear Breakpoint</i></b> menu item.</font></li>
<li>
<font size=-1>Simply single-click on the red dot or the line number of
the line at which you want to clear a breakpoint.</font></li>
</ul>
<font size=-1>The red dot will disappear and the breakpoint at that location
will be cleared.</font>
<p><a NAME="_Toc502165114"></a><b><font face="Arial"><font color="#000080"><font size=+1>Viewing
Variables</font></font></font></b>
<br><font size=-1>The lower-left (dockable) pane in the debugger main window
contains a tab-pane with two tabs, labeled "this" and "Locals". Each pane
contains a tree-table which displays the properties of the current object
and currently visible local variables, respectively.</font>
<p><b><font face="Arial"><font color="#000080">This</font></font></b>
<br><font size=-1>The properties of the current object are displayed in
the
<b><i>this</i></b> table. If a property is itself a JavaScript object
the property may be expanded to show its sub-properties. The <b><i>this</i></b>
table is updated each time control returns to the debugger or when you
change the stack location in the <b><i>Context:</i></b> window.</font>
<p><b><font face="Arial"><font color="#000080">Locals</font></font></b>
<br><font size=-1>The local variables of the current function are displayed
in the <b><i>Locals</i></b> table. If a variable is itself a JavaScript
object the variable may be expanded to show its sub-properties. The <b><i>Locals</i></b>
table is updated each time control returns to the debugger or when you
change the stack location in the <b><i>Context:</i></b> window</font>
<p><a NAME="_Toc502165116"></a><b><font face="Arial"><font color="#000080">Watch
Window</font></font></b>
<br><font size=-1>You may enter arbitrary JavaScript expressions in the
<b><i>Watch:</i></b>
table located in the lower-right (dockable) pane in the debugger main window.
The expressions you enter are re-evaluated in the current scope and their
current values displayed each time control returns to the debugger or when
you change the stack location in the <b><i>Context:</i></b> window.</font>
<p><a NAME="_Toc502165117"></a><b><font face="Arial"><font color="#000080">Evaluation
Window</font></font></b>
<br><font size=-1>The <b><i>Evaluate</i></b> pane located in the lower-right
(dockable) pane in the debugger main window contains an editable command
line where you may enter arbitrary JavaScript code. The code is evaluated
in the context of the current stack frame. The window maintains a history
of the commands you have entered. You may move backward or forward through
the history by pressing the Up/Down arrow keys on the keyboard.</font>
</body>
</html>
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