Function exception_unhandled_handler fixed on HTML5

The problem was during the call to the function the argument being passed was not a valid struct that could be converted into a string on the GML side.
To better mimic the Cpp runner added - message, stacktrace, script - members

Closes: YoYoGames/GameMaker-Bugs#4437

Author: DiasFranciscoA

scripts/_GameMaker.js

@@ -158,8 +158,45 @@ function yyUnhandledExceptionHandler( event )
 		game_end(-1);
 	} // end if
 	else {
-		var ret = g_GMLUnhandledExceptionHandler( undefined, undefined, event.error );
-		game_end( ret );
+        // Create a regular expression pattern to split error stack string.
+        const regexPattern = new RegExp("\n\\s*?at"); 
+
+        let error = event.error; 
+        const message = error.message; 
+
+        // Split the error stack string into an array of call stack entries and remove leading/trailing spaces.
+        // The first entry, usually a message or irrelevant info, is omitted.
+        const stacktrace = error.stack 
+        .split(regexPattern) 
+        .map(entry => entry.trim()) 
+        .slice(1); 
+
+        // Attempt to parse the first call stack entry to identify the script where the error originated.
+        // The script name is assumed to be the substring before the first space in the entry.
+        let script = ""; 
+        if (stacktrace.length > 0) { 
+            const firstEntry = stacktrace[0]; 
+            const firstSpaceIndex = firstEntry.indexOf(' '); 
+            if (firstSpaceIndex !== -1) { 
+                script = firstEntry.substring(0, firstSpaceIndex); 
+            } else { 
+                script = firstEntry; 
+            } 
+        } 
+
+        // Construct a GML struct to encapsulate the error details.
+        let errorStruct = { } 
+        errorStruct.__type = "___struct___"; 
+        errorStruct.__yyIsGMLObject = true; 
+
+        // Add error details to the struct with a "gml" prefix for each member.
+        errorStruct.gmlmessage = message; 
+        errorStruct.gmlstacktrace = stacktrace; 
+        errorStruct.gmlscript = script; 
+
+        // Pass the error struct to the custom error handler
+        var ret = g_GMLUnhandledExceptionHandler( undefined, undefined, errorStruct ); 
+        game_end( ret );
 	}
 	debugger;
 	return false;