In a function, in strict mode,thisisundefined. In an event,thisrefers to theelementthat received the event. Methods likecall(),apply(), andbind()can referthistoany object. Note thisis not a variable. It is a keyword. You cannot change the value ofthis. ...
In most cases, the value of this is determined by how a function is called (runtime binding). ES5 introduced the bind() method to set the value of a function's this regardless of how it's called, and ES2015 introduced arrow functions which don't provide their own this binding (it re...
1 使用 eval() 创建动态函数: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 // 动态生成函数functioncreateDynamicFunctionEval(){constfunctionBody='console.log("动态函数 - eval()");';constdynamicFunction=newFunction(functionBody);returndynamicFunction;}// 调用动态函数constdynamicFuncEval=createDyna...
In most cases, the value of a function'sthisargument is determined by how the function is called. This lesson explains whatthisrefers to when we call plain function. Marius points out how functions behave differently in strict and non-strict mode."use strict"mode defaultsthisto undefined and ...
log(this === undefined); // => true return a * b; } // multiply() function invocation with strict mode enabled // this in multiply() is undefined multiply(2, 5); // => 10 当使用严格模式调用 multiply(2, 5) 的时候,this 就是undefined。 严格模式不仅对当前作用域有效,它内部的作用...
javascript之function的this 一、this 的定义 与 函数的调用 在 javascript 中, function 中的 this 指代的是: 调用 function 执行时的上下文。 也就是说,调用哪个 ...
「The this keyword evaluates to the value of the ThisBinding of the current execution context.」「this 这个关键字代表的值为当前执行上下文的ThisBinding。」然后再来看看MDN 对this 的定义：「In most cases, the value of this is determined by how a function is called.」「在大多数的情况下，this ...
member=2@dmethod(foo:number,bar:Bar,baz:Foo):string{}constructor(a:Bar){}} 转换结果: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 var__metadata=(this&&this.__metadata)||function(k,v){if(typeofReflect==='object'&&typeofReflect.metadata==='function')returnReflect.metadata(k,v)}/...
This behavior has changed in ECMAScript 5 only when using strict mode[2]: AI检测代码解析 // this: hello("world") // desugars to: hello.call(undefined,"world"); 1. 2. 3. 4. 5. The short version is: a function invocation like fn(...args) is the same as ...
关于function中的this指向老觉得很迷惑。 document.body.onclick = function(){ console.log(this); // 这个this指向body function click_inner(){ console.log(this); // 这个this指向了window } click_inner(); } 从上面的代码可以推测出:每个function中都有一个this。 我原先的理解为:click_inner 内没...