diff --git a/tests/showMessage.spec.js b/tests/showMessage.spec.js
index aa81f73..c880d2e 100644
--- a/tests/showMessage.spec.js
+++ b/tests/showMessage.spec.js
@@ -6,7 +6,7 @@ describe('showMessage trial', () => {
     it('showMessage without photodiode box', () => {
         const config = init({USE_PHOTODIODE: false});
         const message = 'Experiment Start'
-        const result = showMessage('html_keyboard_response',100, config, message, false);
+        const result = showMessage('html_keyboard_response',100, config, message, false, false);
         expect(result.stimulus).toContain(message);
         expect(result.stimulus).not.toContain('photodiode-spot');
         expect(result.on_load()).toEqual(null);
@@ -18,7 +18,7 @@ describe('showMessage trial', () => {
         const config = init({USE_PHOTODIODE: true});
         const message = 'Experiment Start'
         let data = { code: null }
-        const result = showMessage('html_keyboard_response',100, config, message, false,10,10);
+        const result = showMessage('html_keyboard_response',100, config, message, false, false,10,10);
         expect(result.stimulus).toContain(message);
         expect(result.stimulus).toContain('photodiode-spot');
         expect(result.on_load()).not.toEqual(null);
@@ -27,14 +27,22 @@ describe('showMessage trial', () => {
 
     it('showMessage with jsPsych.NO_KEYS', () => {
         const config = init({USE_PHOTODIODE: false});
-        const result = showMessage('html_button_response',100, config, false, undefined, undefined, undefined, jsPsych.NO_KEYS);
+        const result = showMessage('html_button_response',100, config, '', false, undefined, undefined, undefined, jsPsych.NO_KEYS);
         expect(result.choices).toEqual(undefined);
     });
 
     it('showMessage with choices', () => {
         const config = init({USE_PHOTODIODE: false});
         const choices = ['p','q']
-        const result = showMessage('html_button_response',100, config, false, undefined, undefined, undefined, choices);
+        const result = showMessage('html_button_response',100, config, '', false, undefined, undefined, undefined, choices);
         expect(result.choices).toEqual(choices);
     });
+
+    it('showMessage with on start message', () => {
+        const config = init({USE_PHOTODIODE: false});
+        const message = 'Experiment Start'
+        let trial = { stimulus: null }
+        const result = showMessage('html_button_response',100, config, message, true, false,10,10);
+        expect(result.on_start(trial)).not.toEqual(null);
+    });
   });
\ No newline at end of file
diff --git a/trials/showMessage.js b/trials/showMessage.js
index 7affb8c..ea27cb0 100644
--- a/trials/showMessage.js
+++ b/trials/showMessage.js
@@ -8,7 +8,7 @@ const { baseStimulus } = require('../lib/markup/stimuli')
  * @param {number} duration - The trial duration in milliseconds.
  * @param {object} config - The configuration object for USE_PHOTODIODE, IS_ELECTRON and USE_MTURK flags.
  * @param {string} message - Onscreen message to be shown in the trial, if not set default text is empty.
- * @param {boolean} onstart - True if the message is to be display on start of the trial. False if the message needs to be in the stimulus.
+ * @param {boolean} onstart - True if the message is to be display on start of the trial. False if the message needs to be in the stimulus.(default: false)
  * @param {boolean} responseEndsTrial - True if the trial ends on response,false if the trial waits for the duration, by default false value.
  * @param {number} taskCode - Task code to be saved into data log and for pdSpotEncode, which by default is null and is passed when config has USE_PHOTODIODE set true.
  * @param {number} numBlinks - Number of times the pulse needs to be repeated for photodiode box, when USE_PHOTODIODE is set true. If not set, by default is 1.
@@ -17,7 +17,7 @@ const { baseStimulus } = require('../lib/markup/stimuli')
 
 
 module.exports = 
-  function(responseType, duration, config, message = "", responseEndsTrial = false, taskCode = null, numBlinks = 1, buttons) {
+  function(responseType, duration, config, message = "", onstart= false, responseEndsTrial = false, taskCode = null, numBlinks = 1, buttons) {
   let stimulus = baseStimulus(`${message}`, true)
   if(config.USE_PHOTODIODE) stimulus += photodiodeGhostBox();