Canvas/AmberPrice_ProgrammingExercise6_13.3.html at master · amberprice-stack/Canvas · GitHub

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<!DOCTYPE html>
<html>
<head>
<style>
        #canvas { width: 400px;
            border: 1px solid #999999;
            border-collapse: collapse }
        td      { width: 4px; height: 4px; margin: 0px; padding: 0px; }
        .blue   { background-color: blue; }
        .red    { background-color: red; }
        .white  { background-color: white; }
    </style>

    <script type="text/javascript">
        function createCanvas() {
            var side = 100;
            var tbody = document.getElementById("tablebody");
            for (var i = 0; i < side; ++i) {
                var row = document.createElement("tr");
                for (var j = 0; j < side; ++j) {
                    var cell = document.createElement("td");
                    row.appendChild(cell);
                }
                tbody.appendChild(row);
            }

            document.getElementById("canvas").addEventListener(
                    "mousemove", processMouseMove, false);
        }

        function processMouseMove(e) {
            if (e.target.tagName.toLowerCase() == "td") {

                if (e.ctrlKey) {
                    e.target.setAttribute("class", "blue");
                }

                if (e.shiftKey) {
                    e.target.setAttribute("class", "red");
                }
                if (e.altKey) {
                    e.target.setAttribute("class", "white");
                }
            }
        }
        window.addEventListener("load", createCanvas, false);
    </script>
</head>
<body>
<table id = "canvas">
    <caption>Hold <em>Ctrl</em> (or <em>Control</em>) to draw blue.
        Hold <em>Shift</em> to draw red. Hold <em>Alt</em> to erase.</caption>
    <tbody id = "tablebody"></tbody>
</table>
</body>
</html>