[monolithed]

я нуб

так писали бы в раздел работа

<script type="text/javascript">
window.onload = function() { 
    var canvas = document.getElementById('canvas'),
        array = [0, 220, 400],
        pol = document.getElementsByName('pol'),
        size = document.getElementsByName('size'),
        button = document.getElementsByName('button')[0],
        d_height = 50, 
        d_width = 50,
        i = pol.length, j,
        ctx = canvas.getContext('2d');
        ctx.fillStyle = "rgba(11,118, 81, 0.5)";
        ctx.fillRect(0, 0, d_width, d_height);
    
    while(i--) {
        pol[i].onchange = function(i) {
            return function() {
                j = i;
            };
    }(i);

    button.onclick = function(i) {
        return function() {
            var width = size[0].value, height = size[1].value;
            ctx.clearRect(0, 0, canvas.width, canvas.height);
            ctx.fillRect(array[j], 0, size[0].value == '' ? d_width : width, size[1].value == '' ? d_height : height);
        };
    }(i);
   }
};
</script>

<form name="forma">
    <input type="radio" name="pol" checked="checked" />Left <br />
    <input type="radio" name="pol" />Center <br />
    <input type="radio" name="pol" />Right <br />
    <input type="text" name="size" value="50" /> Width <br />
    <input type="text" name="size" value="50" /> Height 
    <input type="button" name="button" value="click" />
</form>
<canvas id='canvas' width="500" height="500">Обновите браузер</canvas>