User story

some js frameworks use boolean attribute.

• https://demo.mobiscroll.com/javascript/timeline/work-order-scheduling

Use case

<zk xmlns="native">
    <input type="checkbox" checked />
</zk>

Current result

Caused by: org.xml.sax.SAXParseException: Attribute name "checked" associated with an element type "input" must be followed by the ' = ' character.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException (ErrorHandlerWrapper.java:204)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError (ErrorHandlerWrapper.java:178)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError (XMLErrorReporter.java:400)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError (XMLErrorReporter.java:327)
at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError (XMLScanner.java:1465)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanAttribute (XMLNSDocumentScannerImpl.java:413)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement (XMLNSDocumentScannerImpl.java:250)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next (XMLDocumentFragmentScannerImpl.java:2710)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next (XMLDocumentScannerImpl.java:605)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next (XMLNSDocumentScannerImpl.java:112)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument (XMLDocumentFragmentScannerImpl.java:534)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse (XML11Configuration.java:888)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse (XML11Configuration.java:824)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse (XMLParser.java:141)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse (AbstractSAXParser.java:1216)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse (SAXParserImpl.java:635)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse (SAXParserImpl.java:324)
at javax.xml.parsers.SAXParser.parse (SAXParser.java:330)
at org.zkoss.idom.input.SAXBuilder.build (SAXBuilder.java:298)
at org.zkoss.zk.ui.metainfo.XmlTreeBuilder.parse (XmlTreeBuilder.java:29)
at org.zkoss.zk.ui.metainfo.Parser.parse (Parser.java:120)
at org.zkoss.zk.ui.metainfo.PageDefinitions$MyLoader.parse (PageDefinitions.java:213)
at org.zkoss.zk.ui.metainfo.PageDefinitions$MyLoader.parse (PageDefinitions.java:200)
at org.zkoss.web.util.resource.ResourceLoader.load (ResourceLoader.java:105)
at org.zkoss.web.util.resource.ResourceLoader.load (ResourceLoader.java:35)

Expected Result

no error, render a checked checkbox like an HTML page