For a normal ("Native") JavaScript objects, where the property name is a valid identifier, the expressions x.y and x["y"] are always semantically equivalent.
对于普通（“Native”）JavaScript对象，其中属性名称是有效标识符，表达式x.y和x [“y”]始终在语义上等效。
Is this equivalency guaranteed for Host Objects?
主机对象是否保证等效？
[..an] object supplied by the host environment to complete the execution environment of ECMAScript.
[..an]由主机环境提供的对象来完成ECMAScript的执行环境。
If not, are there notable exceptions? (In Cocoon, Crosswalk, IE, etc?)
如果没有，是否有明显的例外情况？ （在Cocoon，Crosswalk，IE等？）
In particular I am interested in the Window (window) and other DOM Objects; and if there are any known "exceptions" to the expected behavior, or if there are any environments in where such is possible.
特别是我对Window（窗口）和其他DOM对象感兴趣;如果预期行为有任何已知的“例外”，或者存在可能的环境。
1 个解决方案
#1
2
It should be identical. From Section 11.2.1 (Property Accessors) of the Ecma-262 Edition 5.1, we have:
它应该是相同的。从Ecma-262 Edition 5.1的第11.2.1节（属性访问者），我们有：
Properties are accessed by name, using either the dot notation:
使用点表示法按名称访问属性：
MemberExpression . IdentifierName CallExpression . IdentifierNameor the bracket notation:
或括号表示法：
MemberExpression [ Expression ] CallExpression [ Expression ]The dot notation is explained by the following syntactic conversion:
点符号由以下语法转换解释：
MemberExpression . IdentifierNameis identical in its behaviour to
它的行为是完全相同的
MemberExpression [ <identifier-name-string> ]and similarly
和类似的
CallExpression . IdentifierNameis identical in its behaviour to
它的行为是完全相同的
CallExpression [ <identifier-name-string> ]
#1
2
It should be identical. From Section 11.2.1 (Property Accessors) of the Ecma-262 Edition 5.1, we have:
它应该是相同的。从Ecma-262 Edition 5.1的第11.2.1节（属性访问者），我们有：
Properties are accessed by name, using either the dot notation:
使用点表示法按名称访问属性：
MemberExpression . IdentifierName CallExpression . IdentifierNameor the bracket notation:
或括号表示法：
MemberExpression [ Expression ] CallExpression [ Expression ]The dot notation is explained by the following syntactic conversion:
点符号由以下语法转换解释：
MemberExpression . IdentifierNameis identical in its behaviour to
它的行为是完全相同的
MemberExpression [ <identifier-name-string> ]and similarly
和类似的
CallExpression . IdentifierNameis identical in its behaviour to
它的行为是完全相同的
CallExpression [ <identifier-name-string> ]