Strange HTML button postback

I have a webform with lots of <asp:...controls but I need couple of buttons
that doesn't cause an automatic postback. I use javascript to handle these
buttons. I tried two approaches with different results:

<IMG onmouseup="src='Bitmaps/Controls/measure_over.bmp';"
onmousedown="src='Bitmaps/Controls/measure_pressed.bmp';"
id="measure" onmouseover="src='Bitmaps/Controls/measure_over.bmp';"
style="LEFT: 170px; WIDTH: 24px; POSITION: absolute; TOP: 2px; HEIGHT: 25px"
onclick="buttonClicked(this.id);"
onmouseout="src='Bitmaps/Controls/measure_btn.bmp';"
alt="" src="http://pics.10026.com/?src=Bitmaps/Controls/measure_btn.bmp"
This is working the way I want to, but I can't disable it as I can with a
button. I then replace the IMG with:

INPUT Type="image"

and it makes a postback every time I click on it. Why? A HTML control
should't do that, right? The script itself (buttonClicked) just fills a
hidden field.

/MiroFrom the MSDN Library about the <input typ="image" tag:

------------------------
INPUT type=image Element | input type=image Object
Creates an image control that, when clicked, causes the form to be
immediately submitted.
------------------------

Maybe add "onclick='return false;'" to the tag.

-Jason Kendall
JasonKendall@.hotmail.com

On Tue, 1 Feb 2005 05:55:13 -0800, "Miro"
<Miro@.discussions.microsoft.com> wrote:

>I have a webform with lots of <asp:...controls but I need couple of buttons
>that doesn't cause an automatic postback. I use javascript to handle these
>buttons. I tried two approaches with different results:
><IMG onmouseup="src='Bitmaps/Controls/measure_over.bmp';"
>onmousedown="src='Bitmaps/Controls/measure_pressed.bmp';"
>id="measure" onmouseover="src='Bitmaps/Controls/measure_over.bmp';"
>style="LEFT: 170px; WIDTH: 24px; POSITION: absolute; TOP: 2px; HEIGHT: 25px"
>onclick="buttonClicked(this.id);"
>onmouseout="src='Bitmaps/Controls/measure_btn.bmp';"
>alt="" src="http://pics.10026.com/?src=Bitmaps/Controls/measure_btn.bmp">
>This is working the way I want to, but I can't disable it as I can with a
>button. I then replace the IMG with:
>INPUT Type="image"
>and it makes a postback every time I click on it. Why? A HTML control
>should't do that, right? The script itself (buttonClicked) just fills a
>hidden field.
>/Miro