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This article mainly explains "how to judge whether there are parameters in the object with javascript". The content of the explanation in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "how to judge whether there are parameters in the object with javascript".

Javascript method to judge whether there are parameters in an object: use the hasOwnproperty () method, such as [var obj = {a: 1 console.log b: 2 ~ c: 3} console.log (obj.hasOwnProperty ('a'));].

This article operating environment: windows10 system, javascript 1.8.5, thinkpad T480 computer.

Suppose there is an object Object that contains a lot of parameters, but now we need to determine whether a parameter exists in the current object, what should we do?

In fact, it is very simple, by using the hasOwnproperty () method, let's take a look!

Var obj = {a: 1, b: 2, c: 3} console.log (obj.hasOwnProperty ('a')) / / true because the currently defined object contains this parameter, the return value is truevar obj = {a: 1, b: 2, c: 3} console.log (obj.hasOwnProperty ('asd')); / / false returns false at this time because the current object does not contain this value

Its syntax also shows obj.hasOwnProperty (prop).

All objects that inherit Object inherit the hasOwnProperty method. This method can be used to detect whether an object contains specific properties of its own; unlike the in operator, it ignores properties inherited from the prototype chain.

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