make button injection less brittle in list

content.js

@@ -630,30 +630,28 @@ function createRipButton(aid) {
 
 function installTable(tableBody) {
   if (tableBody == null) {
-    console.log("could not install button")
-    return
+    return false
   }
   tableBody.querySelectorAll("tr").forEach((tr) => {
-    if (tr.querySelector(".ripper-btn") != null) return;
+    if (tr.querySelector(".ripper-btn") != null) return true;
     const nameTd = tr.querySelector(".column-name")
     const link = nameTd?.querySelector("a")
     const href = link?.href
     if (href == null) {
-      console.log("could not install button")
-      return
+      return false
     }
     const match = href.match(/^https:\/\/personal\.uni-graz\.at\/#\/job-procedures\/record\/([0-9a-z]{8}-[0-9a-z]{4}-[0-9a-z]{4}-[0-9a-z]{4}-[0-9a-z]{12})/)
     if (match == null) {
-      console.log("could not install button")
-      return
+      return false
     }
     const aid = match[1]
     const actionMenu = tableBody.querySelector("scrm-line-action-menu")
     if (actionMenu == null) {
-      console.log("could not install button")
-      return
+      return false
     }
+    console.log("rip button installed")
     actionMenu.append(createRipButton(aid))
+    return true
   })
 }
 
@@ -671,10 +669,16 @@ function install() {
     titleTag.append(" (", createRipButton(getApplicationId()), ")")
   } else if (window.location.hash === "#/job-procedures/list") {
     /* procedure list page, add the button to each row */
-    setTimeout(() => {
+    let intervalId = -1;
+    let tries = 0;
+    const intervalLoop = () => {
       const tableBody = document.querySelector("scrm-table")?.querySelector("tbody")
-      installTable(tableBody)
-    }, 1000)
+      tries += 1
+      if (installTable(tableBody) || tries > 20) {
+        clearInterval(intervalId)
+      }
+    }
+    intervalId = setInterval(intervalLoop, 100)
   } else {
     console.log("could not install button")
   }