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This article mainly shows you "javascript how to judge the existence of id", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "javascript how to judge the existence of id" this article.

Javascript method to determine the existence of id: 1, to create a HTML example file; 2, to add script tags; 3, through the "function exist (id) {...}" method to determine whether id exists.

This article operating environment: windows7 system, javascript1.8.5 version, Dell G3 computer.

The method of judging the existence of id by js

The code is as follows:

Document// _ window.onload=function () {/ / alert (exist ("getSpanText")); / / alert (exist ("111")) / /} function loadText () {alert (exist (" getSpanText "));} function exist (id) {var s=document.getElementById (id); if (s) {return true} else {return false}}

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