You can access this module with:
可以通过如下方式访问此模块：
var vm = require('vm');JavaScript code can be compiled and run immediately or compiled, saved, and run later.
JavaScript代码可以编译并立即执行，也可以编译后保存，并在以后执行。
vm.runInThisContext() compiles code as if it were loaded from filename,
runs it and returns the result. Running code does not have access to local scope. filename is optional.
vm.runInThisContext()编译并执行code代码，返回执行结果。运行的代码不能访问本地作用域。code代码被视作从filename文件中读取的，filename参数是可选的。
Example of using vm.runInThisContext and eval to run the same code:
使用vm.runInThisContext和eval两种方式运行同样代码的例子：
var localVar = 123,
usingscript, evaled,
vm = require('vm');
usingscript = vm.runInThisContext('localVar = 1;',
'myfile.vm');
console.log('localVar: ' + localVar + ', usingscript: ' +
usingscript);
evaled = eval('localVar = 1;');
console.log('localVar: ' + localVar + ', evaled: ' +
evaled);
// localVar: 123, usingscript: 1
// localVar: 1, evaled: 1vm.runInThisContext does not have access to the local scope, so localVar is unchanged.
eval does have access to the local scope, so localVar is changed.
vm.runInThisContext不能访问本地作用域，所以localVar变量的值没有被修改。eval可以访问本地作用域，因此localVar变量的值被修改了。
In case of syntax error in code, vm.runInThisContext emits the syntax error to stderr
and throws.an exception.
当code代码中存在语法错误时，vm.runInThisContext将错误输出到stderr（标准错误），同时抛出一个异常。
vm.runInNewContext compiles code to run in sandbox as if it were loaded from filename,
then runs it and returns the result. Running code does not have access to local scope and
the object sandbox will be used as the global object for code.
sandbox and filename are optional.
vm.runInNewContext编译并在sandbox（沙箱）中执行code代码，返回执行结果。sandbox对象是代码可以访问的global对象，代码不能访问本地作用域。code代码被视作从filename文件中读取的，sandbox参数和filename参数是可选的。
Example: compile and execute code that increments a global variable and sets a new one. These globals are contained in the sandbox.
例子：编译并执行一段代码，这段代码增加一个global变量的数值，并设置一个新的global变量。这些global变量均存在于沙箱中。
var util = require('util'),
vm = require('vm'),
sandbox = {
animal: 'cat',
count: 2
};
vm.runInNewContext('count += 1; name = "kitty"', sandbox, 'myfile.vm');
console.log(util.inspect(sandbox));
// { animal: 'cat', count: 3, name: 'kitty' }Note that running untrusted code is a tricky business requiring great care. To prevent accidental
global variable leakage, vm.runInNewContext is quite useful, but safely running untrusted code
requires a separate process.
运行不可靠的代码是需要非常小心的有风险的操作。使用vm.runInNewContext方法对防止global变量泄露非常有帮助，但最好还是在一个独立的进程中运行不可靠的代码。
In case of syntax error in code, vm.runInThisContext emits the syntax error to stderr
and throws an exception.
当code代码中存在语法错误时，vm.runInThisContext将错误输出到标准错误，同时抛出一个异常。
createScript compiles code as if it were loaded from filename,
but does not run it. Instead, it returns a vm.Script object representing this compiled code.
This script can be run later many times using methods below.
The returned script is not bound to any global object.
It is bound before each run, just for that run. filename is optional.
createScript方法编译code代码但并不执行它。取而代之，此方法返回一个vm.Script对象以表示编译后的代码。这个脚本对象可以使用下文所介绍的方法运行，并可运行多次。返回的脚本并不与任何global对象绑定，只有在实际运行时才会与global对象绑定，而且绑定只对一次运行有效。code代码被视作从filename文件中读取的，filename参数是可选的。
In case of syntax error in code, createScript prints the syntax error to stderr
and throws an exception.
当code代码中存在语法错误时，createScript 将错误输出到标准错误，同时抛出一个异常。
Similar to vm.runInThisContext but a method of a precompiled Script object.
script.runInThisContext runs the code of script and returns the result.
Running code does not have access to local scope, but does have access to the global object
(v8: in actual context).
这是预编译的Script对象的一个方法，其作用与vm.runInThisContext类似。script.runInThisContext运行script对象的代码并返回结果。运行的代码不能访问本地作用域，但可以访问（v8：实际上下文中的）global全局对象。
Example of using script.runInThisContext to compile code once and run it multiple times:
使用script.runInThisContext一次编译多次执行代码的例子：
var vm = require('vm');
globalVar = 0;
var script = vm.createScript('globalVar += 1', 'myfile.vm');
for (var i = 0; i < 1000 ; i += 1) {
script.runInThisContext();
}
console.log(globalVar);
// 1000Similar to vm.runInNewContext a method of a precompiled Script object.
script.runInNewContext runs the code of script with sandbox as the global object and returns the result.
Running code does not have access to local scope. sandbox is optional.
这是预编译的Script对象的一个方法，其作用与vm.runInNewContext类似。script.runInNewContext将sandbox作为global对象，运行script对象的代码并返回结果。运行的代码不能访问本地作用域。sandbox是可选参数。
Example: compile code that increments a global variable and sets one, then execute this code multiple times. These globals are contained in the sandbox.
例子：编译一段代码并执行多次，这段代码增加一个global变量的数值，并设置一个新的global变量。这些global变量均存在于沙箱中。
var util = require('util'),
vm = require('vm'),
sandbox = {
animal: 'cat',
count: 2
};
var script = vm.createScript('count += 1; name = "kitty"', 'myfile.vm');
for (var i = 0; i < 10 ; i += 1) {
script.runInNewContext(sandbox);
}
console.log(util.inspect(sandbox));
// { animal: 'cat', count: 12, name: 'kitty' }Note that running untrusted code is a tricky business requiring great care. To prevent accidental
global variable leakage, script.runInNewContext is quite useful, but safely running untrusted code
requires a separate process.
运行不可靠的代码是需要非常小心的危险操作。使用script.runInNewContext对防止global变量泄露非常有帮助，但最好还是在一个独立的进程中运行不可靠的代码。