Question

How do you increase the height of an textbox? (along with its font size)

Answer 1

I’m assuming from the way you worded the question that you want to change the size after the page has rendered?

In Javascript, you can manipulate DOM CSS properties, for example:

document.getElementById('textboxid').style.height="200px";
document.getElementById('textboxid').style.fontSize="14pt";

If you simply want to specify the height and font size, use CSS or style attributes, e.g.

//in your CSS file or <style> tag
#textboxid
{
    height:200px;
    font-size:14pt;
}

<!--in your HTML-->
<input id="textboxid" ...>

Or

<input style="height:200px;font-size:14pt;" .....>