ECMAScript
出自OpenFace
Appendix B. ECMAScript
Part XI. Appendices
Including Script
Script can go in four places in an LZX application:
Inside an event attribute such as onclick.
<canvas height="30">
<button onclick="animate('x', 10, 1000, true)">Click</example>
</canvas>
In a <method> or <script> tag.
In an attribute with type expression.
Inside a constraint expression.
In a separate file that is included via the src attribute of the <script> tag.
<canvas> <include href="script.js"/> </canvas>
Differences between ECMA-262 and LZX
The syntax and behaviour of LZX script is intended to be as specified by the ECMA-262 standard. However, there are some differences to be aware of.
Case-sensitivity Identifiers are not case sensitive. For example, Boolean and boolean refer to the same value.
The best practice is to use identifiers with the proper case, as this discrepancy from ECMA-262 will be removed in a future release.
Exceptions There are no exceptions, and no exception handling. try/catch/finally is not supported.
Errors such as 1/0, u(), k(), u.p, and o.u (where u is an undeclared variable, k is defined but isn't a function, and o is an object with property p) are silently ignored. (If debugging is enabled, all but the first of these will generate a warning message in the debugger window when evaluated.)
The best practice for detecting program errors in LZX code is to develop with debugging enabled (Chapter 45, Debugging) and to write unit tests (Chapter 46, Unit Testing).
The best practice for non-local transfer of control is to return a distinguished value or set a state variable.
String conversion When a String appears in a boolean context, only Strings that can be parsed as a non-zero number evaluate to true. The best practice is to use string.length to test for non-empty.
undefined conversion undefined converts to "" in a string context and to 0 in a numeric context. The best practice is to test for undefined explicitly using typeof(expression) == "undefined".
ECMAScript Objects Some ECMAScript objects and properties are not supported. See Table B.1, “Supported ECMAScript Properties” for a list of supported objects.
Browser Objects ECMA-262 is NOT the same as client-side JavaScript as implemented by web browsers. This means that the objects that are browser specific (e.g. window, document, etc.) are not available to the LZX developer.
Unicode Only Latin-1 and Shift-JIS characters are supported.
Forward references Forward references to functions are not supported.
LZX does not support the ECMAScript objects, attributes and methods presented in this font in the following table.
Table B.1. Supported ECMAScript Properties
ECMA Object Properties Methods Arguments callee
length
Array
Array.prototype
constructor
length
Array(...)
new Array(...)
concat(...)
join(separator)
pop()
push(...)
reverse()
shift()
slice(start, end)
sort(comparefn)
splice(start, delete, ...)
toLocalString()
toString()
unshift(...)
Boolean
Boolean.prototype
constructor
Boolean(value)
new Boolean(value)[a] [b]
toString()
valueOf()
Date
Date.prototype
constructor
Date(...)
new Date(ms)
new Date(...)
new Date(string)[c]
parse(string)[c]
Date.UTC(...)
get[UTC]Date()
get[UTC]Day()
get[UTC]FullYear()
get[UTC]Hours()
get[UTC]Millisconds()
get[UTC]Minutes()
get[UTC]Month()
get[UTC]Seconds()
getTime()
getTimezoneOffset()
getYear()
set[UTC]Date(date)
set[UTC]FullYear(year[, month[, date]])
set[UTC]Hours(hours[, min[, sec[, ms]]])
set[UTC]Milliseconds(ms)
set[UTC]Minutes(minutes[, sec[, ms]])
set[UTC]Month(month[, date])
set[UTC]Seconds(sec[, ms])
setTime(ms)
setYear(year)
todateString()
toGMTSting()
toLocaleDateString()
toLocaleString()
toLocaleTimeString()
toString()
toTimeString()
toUTCString()
valueOf()
Error
Error.prototype
constructor
message
name
Error(message)
new Error(message)
toString()
EvalError
EvalError.prototype
constructor
message
name
EvalError(message)
new EvalError(message)
toString()
Function
Function.prototype
constructor
length
Function(...)
new Function(...)
apply(this, args[])
call(this, ...)
toString()
Global
Infinity
NaN
undefined
decodeURI()
decodeURIComponent()
encodeURI(uri)
encodeURIComponent(component)
escape(string)
eval(string)[d]
isFinite(number)
isNaN(number)
parseFloat(string)
parseInt(string[, radix])
unescape(string)
Math
Math.E
Math.LN2
Math.LOG2E[e]
Math.PI
Math.SQRT1_2
Math.SQRT2
abs(x)
acos(x)
asin(x)
atan(x)
atan2(x, y)
ceil(x)
cos(x)
exp(x)
floor(x)
log(x)
max(...)[f]
min(...)[f]
pow(x, y)
random()
round(x)
sin(x)
sqrt(x)
tan(x)
Number
Number.prototype
Number.MAX_VALUE
Number.MIN_VALUE
Number.NaN
Number.NEGATIVE_INFINITY
Number.POSITIVE_INFINITY
constructor
Number(value)
new Number(value)
toString()
toLocalString()
toFixed()
toExponential()
toPrecision()
valueOf()
Object
Object.prototype
constructor
Object()
Object(value)[g]
new Object()
hasOwnProperty(v)
isPrototypeOf(v)
propertyIsEnumerable(v)
toLocalString()
toString()[h]
valueOf()
RangeError
RangeError.prototype
constructor
message
name
RangeError(message)
new RangeError(message)
toString()
ReferenceError
ReferenceError.prototype
constructor
message
name
ReferenceError(message)
new ReferenceError(message)
toString()
RegExp
RegExp.prototype
constructor
global
ignoreCase
lastIndex
multiline
source
RegExp(pattern, flags)
new RegExp(pattern, flags)
exec(string)
test(string)
String
String.prototype
constructor
length
String(value)
new String(value)[i]
String.fromCharCode(...)
charAt(pos)
charCodeAt(pos)
concat(...)
indexOf(searchstr[, start])
lastIndexOf(searchstr[, start])
localeCompare(that)
match(regexp)
replace(searchstr, replacement)
search(regexp)
slice(start[, end])
split(delimiter)
substring(start[, end])
toLocaleLowerCase()
toLocaleUpperCase()
toLowerCase()
toString()
toUpperCase()
valueOf()
SyntaxError
SyntaxError.prototype
constructor
message
name
SyntaxError(message)
new SyntaxError(message)
toString()
TypeError
TypeError.prototype
constructor
message
name
TypeError(message)
new TypeError(message)
toString()
URIError
URIError.prototype
constructor
message
name
URIError(message)
new URIError(message)
toString()
[a] new Boolean() may not be used to coerce a String to a Boolean.
[b] new Boolean() may not be used to clone a wrapper.
[c] new Date(string) and Date.parse() are not supported. Passing a string to new Date(datestring) is not supported. The best practice is to construct dates from date components, for example: in place of new Date("7/20/1969") use new Date(1969, 7, 20).
[d] The eval() function cannot be used to execute arbitrary code. It may only be used only to get the value of an identifier named by a String.
[e] Math.LOG2E is incorrect on the Flash 5 player
[f] Math.max() and Math.min() only support two arguments.
[g] Using Object() to create a wrapper is not supported.
[h] Object.toString always returns "[object Object]".
[i] Using new String(value) to clone a wrapper is not supported.
Reserved Words
Reserved words may not be used as identifiers:
Table B.2. ECMAScript Keywords
Keywords Reserved for future use break for throw case function try catch if typeof continue in var default instanceof void delete new undefined do return while else switch with finally this abstract final protected boolean float public byte goto short char implements static class import super const int synchronized debugger interface throws double long transient enum native volatile export package extends private
A property of an object may have any name, even that of a reserved word. object.property and object['property'] both refer to the property property of the object named object. When using dot syntax (object.property) property names must be a valid identifiers, so object.default, for example, is a syntax error. In this case object['default'] can be used instead.
