When you add a textarea to your webpage it will allow the webpage visitor access to resize the textarea to any size they want horizontal and vertical. In chrome you are only able to resize the textarea on the vertical. There is a CSS property that allows you to control how the user can resize textareas.
resize: both;
resize: horizontal;
resize: vertical;
resize: none;
<textarea style="resize: both;">
Resize the textarea both horizontal and vertical
</textarea>
<textarea style="resize: horizontal;">
Resize horizontal
</textarea>
<textarea style="resize: vertical;">
Resize vertical
</textarea>
<textarea style="resize: none;">
No resizing
</textarea>