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How does javascript determine whether an object exists?

2025-04-02 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Development >

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Editor to share with you how javascript judges whether the object exists or not. I hope you will get something after reading this article. Let's discuss it together.

1. Use the "if (! Obj)" statement.

If (! myObj) {var myObj = {};}

2. Use "if (! window.Obj)".

If (! window.myObj) {myObj = {};}

3. Use "if (! this.Obj)".

If (! this.myObj) {this.myObj = {};}

4. Use "if (typeof Obj==" undefined ")".

Var global = this;if (! global.myObj) {global.myObj = {};}

5. Use "if (Obj==undefined)" and so on.

If (typeof myObj = = "undefined") {var myObj = {};} after reading this article, I believe you have a certain understanding of "how to determine whether an object exists by javascript". If you want to know more about it, welcome to follow the industry information channel. Thank you for reading!

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