Script
Overview
Script contains author-programmed event behaviors for a scene. Define the script input-output event interface by including <field/> elements. Scripting code is embedded in a child CDATA node or (deprecated) in the url field. Optionally supported programming languages are ECMAScript (JavaScript) and Java (via url to a myNode.class file).
The Script node belongs to the Scripting component and requires at least level 1, its default container field is children. It is available since VRML 2.0 and from X3D version 3.0 or higher.
Hierarchy
1
2
3
4
+ X3DNode
+ X3DChildNode
+ X3DScriptNode (X3DURLObject)*
+ Script
* Derived from multiple interfaces.
Fields
SFNode [in, out] metadata NULL [X3DMetadataObject]
Information about this node can be contained in a MetadataBoolean, MetadataDouble, MetadataFloat, MetadataInteger, MetadataString or MetadataSet node.
Hint
SFString [in, out] description “”
Author-provided prose that describes intended purpose of the url asset.
Hint
- Many XML tools substitute XML character references for special characters automatically if needed within an attribute value (such as & for & ampersand character, or " for “ quotation-mark character).
SFBool [in, out] load TRUE
load=true means load immediately, load=false means defer loading or else unload a previously loaded scene.
Hints
- Allows author to design when Inline loading occurs via user interaction, event chains or scripting.
- Use a separate LoadSensor node to detect when loading is complete.
MFString [in, out] url [ ] [URI]
List of address links for runnable script files.
Hints
- Embedded ecmascript: source can also be contained in the sourceCode pseudo-field without escape characters, equivalent to last entry in the url list, when using other API codebases and file encodings.
- Browsers are not required to support any particular scripting language, but ECMAScript (JavaScript) is widely supported.
- Equivalent script code written in multiple programming languages can be provided for portability, the first runnable version is chosen at run time.
- X3D Scene Authoring Hints, Scripts
- If both url field and CDATA section are provided simultaneously, the url field is processed first. This approach allows utilization of update modifications or live queries in external scripts, while still providing reliable script source as a fallback alternative within the model itself.
- X3D XML Encoding, 4.3.13 Encapsulating Script node code
- MFString arrays can have multiple values, so separate each individual string by quote marks “https://www.web3d.org” “https://www.web3d.org/about” “etc.”
- Alternative XML encoding for quotation mark “ is " (which is an example of a character entity).
- Can replace embedded blank(s) in url queries with %20 for each blank character.
- X3D Scene Authoring Hints, urls
Warnings
- Source code can be placed in url attribute but may be unparsable due to escaping of special characters and elimination of line breaks (causing comments to nullify follow-on code). Use contained CDATA section instead for embedding source code.
- Strictly match directory and filename capitalization for http links! This is important for portability. Some operating systems are forgiving of capitalization mismatches, but http/https url addresses and paths in Unix-based operating systems are all case sensitive and intolerant of uppercase/lowercase mismatches.
SFTime [in, out] autoRefresh 0 [0,∞)
autoRefresh defines interval in seconds before automatic reload of current url asset is performed.
Hints
- If preceding file loading fails or load field is false, no refresh is performed.
- Repeated refresh attempts to reload currently loaded entry of url list. If that fails, the browser retries other entries in the url list.
Warning
- Automatically reloading content has security considerations and needs to be considered carefully.
SFTime [in, out] autoRefreshTimeLimit 3600 [0,∞)
autoRefreshTimeLimit defines maximum duration that automatic refresh activity can occur.
Hint
- Automatic refresh is different than query and response timeouts performed by a networking library while sequentially attempting to retrieve addressed content from a url list.
Warning
- Automatically reloading content has security considerations and needs to be considered carefully.
SFBool [ ] directOutput FALSE
Set directOutput true if Script has field reference(s) of type SFNode/MFNode, and also uses direct access to modify attributes of a referenced node in the Scene.
Hints
- Set directOutput true if Script dynamically establishes or breaks ROUTEs.
- directOutput is a browser hint to avoid overoptimizing referenced nodes, since a Script might directly change attribute values in referenced SFNode/MFNode fields, without a ROUTE connecting output events.
- directOutput false means Script cannot modify referenced nodes or change ROUTEs.
SFBool [ ] mustEvaluate FALSE
If mustEvaluate false, then the X3D player may delay sending input events to Script until output events are needed. If mustEvaluate true, then Script must receive input events immediately without any event-aggregation delays.
Hint
- Set mustEvaluate true when sending/receiving values via the network.
Advice
Hints
- Insert an XML Character Data (CDATA) block within the Script node to contain source code embedded within an X3D scene, avoiding the need for escape characters.
- A contained XML Character Data (CDATA) block for source code protects whitespace, line breaks, and literal characters (such as & for ampersand character, < for less-than-sign character, and > for greater-than-sign character) from unintended escape-character modifications by XML parsers.
- X3D Scene Authoring Hints, Scripts
- Apply
containerField='watchList'when parent node is LoadSensor.ECMAScript-262 specification - Embedded ecmascript: source can also be contained in the sourceCode pseudo-field without escape characters, equivalent to last entry in the url list, when using other API codebases and file encodings.
Warning
- Strict order is required for contained constructs: first field declarations (if any), then IS/connect statements (if any), and finally CDATA source-code block.