score:3

Accepted answer

This will find the textarea element in the #thisspecificid

$('#thisspecificid textarea').attr('rows', 20);

Demo: https://jsfiddle.net/tusharj/rwmwyhd6/

Similar question

score:1

You can use .attr() to change it:

$('tr textarea').attr("rows","30");

read more about jquery.attr()

score:2

Note: All id's must be unique and if not please do

To change the textarea to 30 rows (assumed :one textarea) you can do like

$('textarea').attr("rows","30")
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<textarea id=thisspecificid rows=15></textarea>

score:3

You can add type of control in the selector with id to get specific element you want. You can use attribute selector with type of element as under. In the attribute selector use the * as a wild card for elements containing the given string in the id.

$("textarea[id*=rule_definition]").attr('rows','30'); 

If you are sure the id will start with rule_definition you can use starts with selector using ^ instead of *

$("textarea[id^=rule_definition]").attr('rows','30'); 

Related Query

More Query from same tag