_examples/wasm/index.html

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">

		<script src="//cdnjs.cloudflare.com/ajax/libs/codemirror/5.37.0/codemirror.js"></script>
		<script src="//cdnjs.cloudflare.com/ajax/libs/codemirror/5.37.0/mode/scheme/scheme.js"></script>
		<script src="//cdnjs.cloudflare.com/ajax/libs/codemirror/5.37.0/addon/edit/matchbrackets.js"></script>
		<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/codemirror/5.37.0/codemirror.css" />
		<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/codemirror/5.37.0/theme/neat.css" />

		<script src="wasm_exec.js"></script>
		<script>
			const go = new Go();

			function loadEditor() {
				var timer = null;
				var editor = null;

				function editHook(cm, arg) {
					if (timer) {
						clearTimeout(timer);
					}
					timer = setTimeout(loadTextarea, 400);
				}

				function initHook(cm) {
					cm.on("changes", editHook);
					cm.on("update", editHook);
				}

				window.CodeMirror.defineInitHook(initHook);

				editor = window.CodeMirror.fromTextArea(document.getElementById("lisp-source"), {
					"lineNumbers": true,
					"mode": "scheme",
					"matchBrackets": true,
					"indentUnit": 2,
					"tabSize": 2,
					"theme": "neat"});

				function setLispOutput(result, err) {
					var output = document.getElementById("lisp-output");
					output.innerHTML = result;
					var error = document.getElementById("lisp-error");
					error.innerHTML = err;
				}

				function loadTextarea() {
					var value = editor ? editor.getValue() : "";
					var result = new Promise(function(resolve, reject) {
						var context = {
							resolve: resolve,
							reject: reject
						};
						LoadString(value, context);
					});
					result.then(function(value) {
						setLispOutput(value, "")
					}).catch(function(err) {
						setLispOutput("", err)
					});
				}
			}

			// Safari does not have support the function
			// WebAssembly.instantiateStreaming so this hack performs
			// inefficient, non-streaming compilation and instatiation.
			var appWasm = fetch("app.wasm")
				.then((source) => { return source.arrayBuffer(); })
				.then((buffer) => { return WebAssembly.instantiate(buffer, go.importObject); })
				.then((result) => { go.run(result.instance); loadEditor(); });

		</script>

	</head>
	<body>
		<div class="input">
			<div class="source">
				<textarea id="lisp-source" style="min-width: 500px; min-height: 100px;">(+ 2 1)</textarea>
			</div>
		</div>
		<div class="output">
			<pre id="lisp-output">
			</pre>
		</div>
		<div class="error">
			<pre id="lisp-error" style="color: red;">
			</pre>
		</div>
	</body>
</html>