The font-size property affects the size of an element's text.
xx-small − Sets the element's text to be a size smaller than that which results from the value x-small.
x-small − Sets the element's text to be a size smaller than that which results from the value small.
small − Sets the element's text to be a size smaller than that which results from the value medium.
medium − Sets the element's text to be a size smaller than that which results from the value large, and larger than that which results from the value small.
large − Sets the element's text to be a size larger than that which results from the value medium.
x-large − Sets the element's text to be a size larger than that which results from the value large.
xx-large − Sets the element's text to be a size larger than that which results from the value x-large.
larger − Sets the element's text to be larger than that of its parent.
smaller − Sets the element's text to be smaller than that of its parent.
length − Any permitted length value. Negative length values are not permitted for font-size.
percentage − Sets the element's text size relative to that of its parent.
All the HTML elements.
object.style.fontSize = "12pt";
Here is the example using this property −
<html> <head> </head> <body> <p style = "font-size:20px;"> This font size is 20 pixels </p> <p style = "font-size:small;"> This font size is small </p> <p style = "font-size:large;"> This font size is large </p> </body> </html>
This will produce following result −