Using class name instead of ids

src/main/resources/com/cloudbees/jenkins/plugins/sshcredentials/impl/BasicSSHUserPrivateKey/DirectEntryPrivateKeySource/config.jelly

@@ -26,6 +26,6 @@
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:f="/lib/form">
   <f:entry title="${%Key}" field="privateKey">
-    <f:secretTextarea checkMethod="post" id="sshCredentials_privateKey"/>
+    <f:textarea checkMethod="post" class="sshCredentials_privateKey"/>
   </f:entry>
 </j:jelly>

src/main/resources/com/cloudbees/jenkins/plugins/sshcredentials/impl/BasicSSHUserPrivateKey/credentials.jelly

@@ -38,7 +38,7 @@
     <f:hetero-radio field="privateKeySource" descriptors="${descriptor.privateKeySources}"/>
   </f:entry>
   <f:entry title="${%Passphrase}" field="passphrase">
-    <f:password id="sshCredentials_passphrase"/>
+    <f:password clazz="sshCredentials_passphrase"/>
   </f:entry>
   <st:adjunct includes="com.cloudbees.jenkins.plugins.sshcredentials.impl.BasicSSHUserPrivateKey.passphraseChangeEvent" />
 </j:jelly>

src/main/resources/com/cloudbees/jenkins/plugins/sshcredentials/impl/BasicSSHUserPrivateKey/passphraseChangeEvent.js

@@ -1,8 +1,13 @@
 //TODO: this snippet, as well as ids in passphrase and private key fields can be removed once https://issues.jenkins.io/browse/JENKINS-65616 is completed
-var passphraseElement = document.getElementById('sshCredentials_passphrase');
-var privateKeyElement = document.getElementById('sshCredentials_privateKey');
+const passphraseElements = document.getElementsByClassName('sshCredentials_passphrase');
 
-passphraseElement.addEventListener("change", event => {
-    var newEvent = new Event("change")
-    privateKeyElement.dispatchEvent(newEvent)
-})
+if (passphraseElements.length > 0) {
+// Failsafe in case there's more than 1 element we'll only use the first one. Should not happen.
+    passphraseElements[0].addEventListener("change", event => {
+        var newEvent = new Event("change")
+        const privateKeyElements = document.getElementsByClassName('sshCredentials_privateKey');
+        if (passphraseElements.length > 0) {
+            privateKeyElements[0].dispatchEvent(newEvent)
+        }
+    })
+}