Question

I am trying to make a webpage where when you click a link, the link moves diagonally every 100 milliseconds.

So I have my Javascript, but right now when I click the link nothing happens

Also, does anyone know of a Javascript IDE I can use to make sure I have no errors in my code?

PS: Does anyone know why my elements dont stretch to fit the whole 200px by 200px of the div element? The links are only small when they should be the same width as their parent div element.

Edited with new advice, although still wont move.

<script LANGUAGE="JavaScript" type = "text/javascript">
<!--
    var block         = null;
    var clockStep     = null;
    var index         = 0;
    var maxIndex      = 6;
    var x             = 0;
    var y             = 0;
    var timerInterval = 100;  // milliseconds
    var xPos          = null;
    var yPos          = null;

    function moveBlock()
    {
        if ( index < 0 || index >= maxIndex || block == null || clockStep == null ) 
        { 
            clearInterval( clockStep );
            return;
        }

        block.style.left = xPos[index] + "px";
        block.style.top  = yPos[index] + "px";
        index++;
    }

    function onBlockClick( blockID )
    {
        if ( clockStep != null )
        {
            return;
        }

        block = document.getElementById( blockID );
        index = 0;
        x = parseInt( block.style.left, 10 );
        y = parseInt( block.style.top, 10 );
        xPos  = new Array( x+10, x+20, x+30, x+40, x+50, x+60 );
        yPos  = new Array( y-10, y-20, y-30, y-40, y-50, y-60 );

        clockStep = self.SetInterval( moveBlock(), timerInterval );
    }
-->
</script>
<style type="text/css" media="all">
    <!--
    @import url("styles.css");

    #blockMenu { z-index: 0; width: 650px; height: 600px; background-color: blue; padding: 0; }

    #block1 { z-index: 30; position: relative; top: 10px;  left: 10px; background-color: red; width: 200px; height: 200px; 
              margin: 0; padding: 0; /* background-image: url("images/block1.png"); */ }
    #block2 { z-index: 30; position: relative; top: 50px; left: 220px; background-color: red; width: 200px; height: 200px; 
              margin: 0; padding: 0; /* background-image: url("images/block1.png"); */ }
    #block3 { z-index: 30; position: relative; top: 50px; left: 440px; background-color: red; width: 200px; height: 200px; 
              margin: 0; padding: 0; /* background-image: url("images/block1.png"); */ }
    #block4 { z-index: 30; position: relative; top: 0px; left: 600px; background-color: red; width: 200px; height: 200px; 
              margin: 0; padding: 0; /* background-image: url("images/block1.png"); */ }

    #block1 a { display: block; width: 100%; height: 100%; }
    #block2 a { display: block; width: 100%; height: 100%; }
    #block3 a { display: block; width: 100%; height: 100%; }
    #block4 a { display: block; width: 100%; height: 100%; }

    #block1 a:hover { background-color: green; }
    #block2 a:hover { background-color: green; }
    #block3 a:hover { background-color: green; }
    #block4 a:hover { background-color: green; }

    #block1 a:active { background-color: yellow; }
    #block2 a:active { background-color: yellow; }
    #block3 a:active { background-color: yellow; }
    #block4 a:active { background-color: yellow; }

    -->
</style>

Answer 1

Errors needed to fix

To fill the width of the div elements, the a elements need to be display: block; not their default display: inline;.

Knowing runtime errors is more important in my opinion, and IDEs don’t catch DOM errors or anything more complex than syntax; use the error logging in your browser (Firefox’s is called Error Console). That’ll also catch in-development errors like syntax errors.

This is the most important point to stress: block.style.left and block.style.top are not just numbers with implicit pixel values in them. Setting it to a number without a unit suffix will do absolutely nothing. You need to add % or px or whatever unit when setting left and top.

When getting the current value, as in var x = ... and var y = ..., you need to Number() manually to get the numeric portion of the string.

Also, I believe you meant || block == null, not =, which would set block to null.

Tips

You can use moveBlock instead of "moveBlock();" as an argument to setTimeout. This avoids parsing the string into code, and avoids scope problems (though not in this example as moveBlock is global).

I know that you have an array of values, where both x and y move 10 each time. I assume you want to move at a 45 degree angle. If so, this won’t work as you expect even after fixing all the errors as x is percentage and y is in pixels.