xpath.js

    function xpath(elm, expr) {                                                                                                                                                                                                            
        var it = document.evaluate(expr, elm, null, XPathResult.ANY_TYPE, null);                                                                                                                                                           
        var typ = it.resultType;                                                                                                                                                                                                           
        switch(typ) {                                                                                                                                                                                                                      
        case XPathResult.NUMBER_TYPE:                                                                                                                                                                                                      
            return it.numberValue;                                                                                                                                                                                                         
        case XPathResult.STRING_TYPE:                                                                                                                                                                                                      
            return it.stringValue;                                                                                                                                                                                                         
        case XPathResult.BOOLEAN_TYPE:                                                                                                                                                                                                     
            return it.booleanValue;                                                                                                                                                                                                        
        default: {                                                                                                                                                                                                                         
            var rows = [];                                                                                                                                                                                                                 
            var node = it.iterateNext();                                                                                                                                                                                                   
            while(node!=null) {                                                                                                                                                                                                            
                if(node instanceof Text) {                                                                                                                                                                                                 
                    rows.push( node.textContent );                                                                                                                                                                                         
                } else {                                                                                                                                                                                                                   
                    rows.push( node );                                                                                                                                                                                                     
                }                                                                                                                                                                                                                          
                node = it.iterateNext();                                                                                                                                                                                                   
            }                                                                                                                                                                                                                              
            return rows;                                                                                                                                                                                                                   
        }}                                                                                                                                                                                                                                 
    }                                                                                                                                                                                                                                      
    function xpath_(elm, expr) {                                                                                                                                                                                                           
        var ret = xpath(elm, expr);                                                                                                                                                                                                        
        if(Array.isArray(ret)) {                                                                                                                                                                                                           
            return ret[0];                                                                                                                                                                                                                 
        } else {                                                                                                                                                                                                                           
            return ret;                                                                                                                                                                                                                    
        }                                                                                                                                                                                                                                  
    }