To change the height, a new function is created which changes the style property of the textarea. The height of the textarea is first set to auto. This value makes the browser set the height of an element automatically. This will make the text scrollable as the textarea height is lesser than the text. Immediately on the next line, the height is again set equal to that of the scrollHeight.
The scrollHeight property is used to return the entire height of an element including padding in pixels. This will make the textarea height equal to the height of the whole text area, effectively resizing the textarea to fit the text.
The ‘input’ event is fired whenever the value of an input or textarea changes. This event can be detected using the addEventListener() method. The callback function of this method is set to the new function created above. This will trigger the textarea to resize whenever any text input is detected, therefore automatically resizing according to the text being typed or pasted.
Method 2: Using jQuery.
It is similar to the above-used method. The on() method in jQuery is used to attach an event handler to any element. The textarea is first selected and this method is used to apply an event handler on the selected element.
A new function is declared in the callback which changes the style property of the textarea. The height of the textarea is first set to ‘auto’ and then immediately on the next line, the height is again set equal to that of the scrollHeight.
This will make the textarea’s height equal to the height of the whole text area, effectively resizing the textarea to fit the text. This function would be executed whenever a change in input is detected and the textarea would appear to resize automatically.