set focus in a textbox

[dhj]

i have a web page which contains several textboxes

my final textbox is to enter a date, near that textbox there is a button, on onclick event of this button small calendar will appear and when the user selects a date from the calendar, the calendar will disapear and selected date is written in the textbox

 

my problem is when i click on calendar the page jump to the top of the page, i do not want to happen this

 

i read abt this on the web, all i found was to use something like "focus" to the textbox

 

but there's no such a property like that in textboxes

does anybody have an idea ?

i'm using .net and C# to develop my web application

 

thanks

[bungpeng]

You may need to control it using javascript