The VRML 97 specification does not require that a VRML browser
support the use of JavaScript to create program scripts for
Script nodes.
Fortunately, most VRML browsers do support JavaScript program scripts,
though you should check your VRML browser's release notes to be sure
it is JavaScript-enabled.
Some VRML browsers, particularly those from Silicon Graphics, support
a derivative of JavaScript called VRMLscript. The language
is essentially identical to JavaScript. Because of Silicon Graphics'
strength in the VRML market, most VRML browser vendors have modified
their VRML browsers to support VRMLscript as well as JavaScript.
JavaScript and VRMLscript program scripts are included as text
within the
url field of a
Script node. To indicate the
program script's language, the field value starts with either
"javascript:" for JavaScript,
or "vrmlscript:" for VRMLscript, like this:
For compatibility with Silicon Graphics VRML browsers, all JavaScript
program script examples in these notes are
tagged as "vrmlscript:",
like the above example. If you have a VRML browser that does not
support VRMLscript, but does support JavaScript, then you can convert
the examples to JavaScript simply by changing the tag
"vrmlscript:"
to "javascript:" like this:
If your VRML browser doesn't support JavaScript or VRMLscript, then
those worlds that
use these languages will produce an error when loaded into your VRML browser.
This is unfortunate since JavaScript or VRMLscript is an essential
feature that all VRML browsers should support. I recommend that you
consider getting a different VRML browser.
If you can't get another VRML browser right now, there are only a
few VRML worlds in these tutorial notes that you will not be able to view.
Those worlds are contained as examples in the following tutorial sections:
So, if you don't have a VRML browser with JavaScript or VRMLscript support,
just skip the above sections and everything will be fine.
Script {
field SFFloat bounceHeight 1.0
eventIn SFFloat set_fraction
eventOut SFVec3f value_changed
url "vrmlscript:
function set_fraction( frac, tm ) {
y = 4.0 * bounceHeight * frac * (1.0 - frac);
value_changed[0] = 0.0;
value_changed[1] = y;
value_changed[2] = 0.0;
}"
}
Script {
field SFFloat bounceHeight 1.0
eventIn SFFloat set_fraction
eventOut SFVec3f value_changed
url "javascript:
function set_fraction( frac, tm ) {
y = 4.0 * bounceHeight * frac * (1.0 - frac);
value_changed[0] = 0.0;
value_changed[1] = y;
value_changed[2] = 0.0;
}"
}