[Original] Why is the height of the text box different?

Today, a strange phenomenon occurs. An input is different on two different pages. I have already written <input id = "txtkeyword" type = "text" style = "height: 20px; width: 204px;"/>. The height is still different!

I was so depressed for half an hour... later, I asked my colleagues to come and see it. After 10 minutes, he had an answer.

<! Doctype HTML public "-// W3C // dtd xhtml 1.0 transitional // en" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >

The above sentence was added to another page, so we encountered a similar problem. First, check if it was my problem!