How to Retrieve Multiple Elements with the Same ID in JavaScript?

Managing Multiple Elements with the Same ID in JavaScript

In JavaScript, getElementById is a method used to retrieve an element based on its ID attribute. However, what happens when multiple elements have the same ID?

Problem Statement:

How can we retrieve a collection of elements with the same ID attribute using getElementById?

Discussion and Solution:

While it is not recommended to use multiple identical IDs within a web page, there may be instances where this occurs. To address this issue, we can employ workarounds:

One approach is to use querySelectorAll, which returns a collection of elements matching the specified selector. Here's an example:

var elms = document.querySelectorAll("[id='duplicateID']");

// Access and modify the elements as needed...

By using the CSS selector with the square brackets, we can retrieve all elements with the specified ID value, even if it appears multiple times.

Alternatively, if we must use getElementById exclusively, we can iteratively retrieve the elements by their ID values and add them to an array:

var elms = [];
var id = "duplicateID";

// Loop through all elements with the specified ID...
while (document.getElementById(id)) {
  // Add the element to the array...
  elms.push(document.getElementById(id));

  // Increment the id to avoid duplicates...
  id += "_duplicate";
}

// Access and modify the array of elements...

By incrementing the ID value in each iteration, we effectively create unique IDs that can be accessed using getElementById.

Remember that using multiple identical IDs can lead to unexpected behaviors and it's generally not a recommended practice. However, these workarounds can be helpful in handling existing codebases or when working with third-party HTML documents.

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