rendered paste body<html> <head> </head> <body> <div style="border: #000 1px solid; text-align: center; width: 300px;" id="div1"> <p style="border: #000 1px solid; text-align: left; margin-left: auto; margin-right: auto; width: 100px; "> test </p> </div> <input type="button" value="-10" onclick="document.getElementById('div1').style.width = (parseInt(document.getElementById('div1').style.width)-10)+'px';" /> <input type="button" value="+10" onclick="document.getElementById('div1').style.width = (parseInt(document.getElementById('div1').style.width)+10)+'px';" /> </body></html>