Script

Scripts are programs that embed in a HTML document. Scripts may modify the document dynamically, response events such as mouse moving, and generate GUI. One kind of script executes one time when a document is loaded. Another kind of script is triggered whenever a specific event occurs.

1. Script

_script command defines a script in its content. It maybe nested and appeared any times. 'type' and 'src' attribute specify the scripting language (e.g. text/javascript) and the location of an external script respectively.

_script "type='text/javascript'"
  # ... JavaScript
script_        

2. Event

   Intrinsic events will active script to execute. There are many events for client interactive controls.

   onload it occures after loading a frame or window. used in _frameset or _body.	onunload it occures when a browser removes a doc. used in _frameset or _body.
   onclick it occures when mouse is clicked over an element.	ondbclick it occures when mouse is double clicked over an element.
   onmousedown it occures when mouse button is pressed on an element.	onmouseup it occures when mouse button is released over an element.
   onmouseover it occures when mouse moved onto an element.	onmousemove it occures when mouse moved while it is over an element.
   onmouseout it occures when mouse moved away from an element.	onkeypress it occures when a key is pressed and released over an element.
   onkeydown it occures when a key is pressed down over an element.	onkeyup it occures when a key is released over an element.
   onfocus it occures when an element receives focus. used with _label, _input, _select, _textarea, and _button commands.	onblur it occures when an element loses focus. used like 'onfocus'.
   onsubmit it occures when a form is submitted. used with _form.	onreset it occures when a form is reseted. used with _form.
   onselect it occures when user selects a text clip in a text field. used with _input and _textarea.	onchange it occures when a control loses the input focus and its value has been modified _input, _select, or _textarea.

3. Activation

   The intrinsic event has a value of script. An event actives the executation of a script. Script's syntax is dependent on the scripting language. Except the Javascript and VB Script, Snaml is also suitable to write a script.

   The _noscript command provides alternate content when a script is not executed. A better practice is adding _comment command in the script content. A browser that does not recognize the scripting language will ignore them.

   _input "name='edit1' size='32'"
   _script "type='text/Snaml'"
     _comment
     proc edit1_changed {} {
       if {[edit value] == "Snaml"} {
         button1 enable 1
       } else {
         button1 enable 0
       }
     }
     edit1 onChange edit1_changed
     comment_
   script_