Script

End Tag: Required
Support Key: 2 | 3 | 3.2* | 4 | IE3B1 | M | N2B3 		What is it?
Attributes
Tag Example 		Parent/Content Model
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[NOTICE: It has become patently obvious to me that I still do not know enough about scripting - both JavaScript and VBScript - to write an adequate page to even scratch the surface of the capabilities of these engines, even to the extent of how they interface with HTML. I will try to remedy this, but in the meantime please consult the Related Links for pointers to sites that cover this topic in much greater depth. Thanks, -ed.]

What is it?
The Script element is the method used by browsers to recognize scripting languages in an HTML document. Scripting allows web pages to change dynamically in response to events such as screen exit and entry, or user mouse-clicks. The most popular browser scripting languages currently are JavaScript and VBScript. While discussing the full scope of scripting in HTML pages is not the intent of these documents, discussion of how scripting affects HTML authoring is DEFINITELY relevant. Many other sites have covered the details with far greater skill and detail than I could ever manage. Please see the Related Links section for pointers to good resources on the subject.

Scripts can exist either embedded within a document or may be located elsewhere. If the script code is contained within a web page, it will be embedded within an HTML comment between the Script container tags (nesting within a comment is important in order to make the script invisible to browsers that do not support the feature.) Statements are evaluated when the document is loaded. If a Script attempts to reference document objects defined by HTML elements occurring later in the document, the attempt will fail. Because of this, it is generally safest to place a SCRIPT statement at the top of a document in the HEAD element.

NOTE: Scripts can also be invoked using the A element combined with Script code in place of the destination URL. This allows a script (either inline or located in a SCRIPT element) to be executed when the user clicks on a hyperlink.
Syntax: [script-engine]:[script-code]
Where [script-engine] is the name of the scripting language used, and [script-code] is either in-line script code or script code referenced elsewhere in the document.
Example: (displays an alert message box that contains the text 'hi there')
<a HREF="JavaScript:alert('hi there')">Click me to see a message.</a>

Specific Attributes
Charset
2 | 3 | 3.2 | 4 | IE | M | N
Required? No
Description:
This indicates the character encoding of the script contents.
Values:
A recognized RFC 2045 language character set string. Default is ISO-8859-1.
Defer
2 | 3 | 3.2 | 4 | IE | M | N
Required? No
Description:
This stand alone attribute is used to advise the browser that the script is not going to generate any rendered document content and thus, the user agent can continue parsing and rendering.
Values: NA
Language
2 | 3 | 3.2 | 4 | IE3B1 | M | N2B3
Required? No
Description:
This attribute indicates the scripting language the script is written in. It is required if the SRC attribute is not specified, optional otherwise.
Values:
The two most popular scripting languages currently are JavaScript and VBScript.
Src
2 | 3 | 3.2 | 4 | IE3.01 | M | N3B5
Required? No
Description:
This attribute specifies an external source for the script code.
Values: An absolute or relative URL
Type
2 | 3 | 3.2 | 4 | IE?? | M | N??
Required? No
Description:
This attribute specifies the MIME type of the scripting code.
Values: Alphanumeric MIME type
Event Handlers
By adding new attributes to HTML elements, a SCRIPT can be linked to a dynamic document action related to a particular element. These attributes are known as "Event Handlers" and they serve to catch document events and trigger script code. The A, BODY, FORM, and INPUT elements were the first allowed to attach event handlers, but that has now grown to include dozens of events applicable to most ANY element now.
Event Handler Quick Index
onBlur | onChange | onClick | onFocus | onLoad
onMouseOver | onSelect | onSubmit | onUnload
onBlur
Attribute of: ilayer, layer, select, text, textarea
Example: <input TYPE="text" NAME="userName" onBlur="required(this.value)">
Description:
A blur Event Handler executes Script code when a form field or layer loses focus.

onChange
Attribute of: select, text, textarea
Example: <input TYPE="text" NAME="userName" onChange="checkValue(this.value)">
Description:
A change Event Handler executes Script code when a form field loses focus and its value has been modified. This event handler is used to validate data after it is modified by a user.

onClick
Attribute of: button, checkbox, radio, hyperlink, reset, submit
Example: <a HREF="" NAME="userName" onClick="this.href=pickRandomURL()">
Description:
A click Event Handler executes Script code when an object is clicked.

onFocus
Attribute of: ilayer, layer, select, text, textarea
Example: <input TYPE="textarea" NAME="valuefield" onFocus="valueCheck()">
Description:
A focus Event Handler executes Script code when a form field or layer receives input focus by tabbing with the keyboard or clicking with the mouse. Important: Selecting within a form field results in a onSelect event, not a onFocus event.

onLoad
Attribute of: body, frameset, ilayer, layer
Example: <body onLoad="window.alert('Welcome to the Brave New World home page!')">
Description:
This attribute executes Script code with the completion of loading of a window, layer, or when all frames within a Frameset have finished loading. In a Frame document scenario, an onLoad event in the BODY element of a sub-frame will occur before an onLoad event within the parent FRAMESET element.

onMouseOver
Attribute of: hyperlink, ilayer, layer
Example: <a HREF="URL" NAME="userName" onMouseOver="window.status='Click this if you dare!'; return true">
Description:
A mouseOver Event Handler executes Script code once each time the mouse pointer enters the bounds of an object from outside the object.

onMouseOut
Attribute of: hyperlink, ilayer, layer
Example: <a HREF="URL" NAME="userName" onMouseOut="window.status='Click this if you dare!'; return true">
Description:
A mouseOout Event Handler executes Script code once each time the mouse pointer exits the bounds of an object from inside the object.

onSelect
Attribute of: text, textarea
Example: <input TYPE="text" NAME="valueField" onSelect="selectState()">
Description:
A select Event Handler executes Script code when a user selects some of the text within a form field.

onSubmit
Attribute of: form
Example: <form onSubmit="return formData(this)">
Description:
A submit Event Handler executes Script code when a user submits a form. It can also be used to prevent a form from being submitted; to do so, put a return statement that returns false in the event handler. Any other returned value lets the form submit. If you omit the return statement, the form is submitted.

onUnload
Attribute of: body, frameset
Example: <body onUnload="cleanUp()">
Description:
An unLoad Event Handler executes Script code when the user exits a document. In a Frame document scenario, an onUnload event in the BODY element of a sub-frame will occur before an onUnload event within the parent FRAMESET element.
Example
<html>
<head>
   <script LANGUAGE="JavaScript">
      <!-- hide script from old browsers
      function getname(str) {
      alert("Hi, "+ str+"!");
      }
      // end hiding contents -->
   </script>
</head>
<body>
   Please enter your name:
   <form>
      <input TYPE="text" NAME="name" onBlur="getname(this.value)" VALUE="">
   </form>
</body>
</html>
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%In-line Parent% | %Block Parent% | <Head>
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%Text% | <!-- -->
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