REPORT-495: Added the onchange function for the DatePicker

Author: IamMujuziMoses

omod/src/main/java/org/openmrs/module/htmlwidgets/web/html/DateWidget.java

@@ -18,6 +18,7 @@ public void render(WidgetConfig config, Writer w) throws IOException {
 		HtmlUtil.renderResource(w, config.getRequest(), "/scripts/calendar/calendar.js");
 
 		Object idPrefix = config.getId();
+		config.setFixedAttribute("onchange", "disableButtons('" + idPrefix + "')");
 		config.setFixedAttribute("onkeyup", "disableButtons('" + idPrefix + "')");
 		config.setFixedAttribute("size", "10");
 		config.setFixedAttribute("onClick", "showCalendar(this);");