Add WPM display

static/index.html

@@ -220,6 +220,8 @@
 							<p>
 								Dit length (iambic):
 								<output id="iambic-duration-value"></output>ms
+								/
+								<output id="iambic-duration-wpm"></output> WPM
 								<input
 									id="iambic-duration"
 									class="mdl-slider mdl-js-slider"

static/vail.mjs

@@ -182,11 +182,15 @@ class VailClient {
 			element.value = storedValue
 		}
 		let outputElement = document.querySelector(selector + "-value")
+		let outputWpmElement = document.querySelector(selector + "-wpm")
 		element.addEventListener("input", e => {
 			localStorage[element.id] = element.value
 			if (outputElement) {
 				outputElement.value = element.value
 			}
+			if (outputWpmElement) {
+				outputWpmElement.value = (1200 / element.value).toFixed(1)
+			}
 			if (callback) {
 				callback(e)
 			}