XML validation 13 December 2003

<script type="text/javascript">
    function xmlValidate( sValue ){
        if( sValue ){
            // cut command
            sValue = sValue.replace( /<\?.*\?>/g, '' );
            // cut doctype
            sValue = sValue.replace( /<\!DOCTYPE.*?>/g, '' );
            // cut comments and CDATA
            var rTags = /(<!--.*?-->|<\!\[CDATA\[.*?\]\]>)/g;
            while( sValue.search( rTags ) >= 0 ){
                sValue = sValue.replace( rTags, '' );
            }
            // cut single quoted strings
            sValue = sValue.replace( /<\w[-\w:]*(\s+[-\w:]+\s*=\s*(["'])[^<>]*?\2)*\s*\/>([^<]*)/gi, '' );
            // cut double quoted strings
            var rTags = /<(\w[-\w:]*(\s+[-\w:]+\s*=\s*(["'])[^<>]*?\3)*\s*>[^<>]*?<\/\1>([^<]*)/g;
            while( sValue.search( rTags ) >= 0 ){
                sValue = sValue.replace( rTags, '' );
            }
            if( sValue.search( /[<>]/ ) >= 0 || sValue.search( /&(?!(\w+;|#\d+;))/ ) >= 0 ){
                //alert( sValue )// may display sValue;
                return false;
            }
            return true;
        }else{
            return true;
        }
    }
</script>
<form name="example" onsubmit="return false">
    <textarea name="text" style="width: 100%; height: 10em;"></textarea>
    <input type="button" value="Validate"
        onclick="if( xmlValidate( document.example.text.value ) )
        { alert( 'It's OK!' ) }else{ alert( 'Not an XML!' ); }" />
</form>