Get value from image button when clicked?

// 1. How to make the image name became variable when it is clicked in php?

echo("<IMG SRC="arrow1.gif" NAME="trade" >");

// 2. I can use isset($_POST['trade']) function to know the button
has been clicked when the input type is "submit", and can get
value by $_POST['trade']. But how to let php page know whether
the image button has been clicked, and how to get value in the
following 2 cases?

// use input element, but the type is image
echo("<input type="image" src="arrow1.gif" name="trade" value="".$symbol"">");

// use button element
echo("<button name="trade" value="".$symbol."" type="button">trade
<img src="arrow1.gif"></button>");

Thanks!

Just add a variable on the end of the images href link. So if you have an image called "home.gif" you would put something to the effect of this

<a href="index.php?image=home"><img src="images/home.gif" border="0"></a>

Thank you very much!

If I use text or image link, i can use Anchor, but how to make a link to the <input type="button"> or <Button>, I can't use Anchor to it.

If you need only do it with a single image, use the submit button as the image. Otherwise you can use JavaScript to set the value of a hidden field when the button is clicked. Alternatively, you could use checkboxes. How many images does this need to be applied to?

The problem with using buttons to pass variables is that the user cannot tell whether the button is selected or not - i.e. when using checkboxes, it has a checked state and an unchecked state, push buttons do not.