What is the Difference Between Substr and Substring

There are two String methods in JavaScript, namely, <kbd class="highlighted">substr()</kbd> and <kbd class="highlighted">substring()</kbd>, that are used to extract a portion of a string. However, there are slight differences between <kbd class="highlighted">substr()</kbd> and <kbd class="highlighted">substring()</kbd> methods.

Both methods can take two parameters, but <kbd class="highlighted">substr()</kbd> uses a start index and a length, while <kbd class="highlighted">substring()</kbd> uses a start index and an end index (excluding).

substr()

<p>The <kbd class="highlighted">substr()</kbd> method is used to get a part of the string that starts at the specified index and extends for a specified number of characters afterwards. Here’s an example of the <kbd class="highlighted">substr()</kbd> method:

Javascript substr method

substring()

The <kbd class="highlighted">substring()</kbd> method is used to get the portion of the string that is between the start and end indexes, or to the end of the string. Here’s an example of the <kbd class="highlighted">substring()</kbd> method:

Javascript substring method

Note that substring() treats negative indices as 0, unlike substr() which counts from the end of the string.

Though <kbd class="highlighted">substr()</kbd> is not strictly a deprecated function, it is considered a legacy feature and you should avoid using it whenever possible. It is officially deprecated in the ECMAScript specification and may be removed in the future. So, you can use the <kbd class="highlighted">substring()</kbd> method instead.