Simple html fragment parser

html.js

parse=(function(document,r_start,r_attr,r_end,cache){
        
        
        return function(str){
            //If there is already a cached element, return its clone
            if(cache[str]) return cache[str].cloneNode(true)
            
            //frag and par are originally the same. par is the current parent and frag is the document fragment being returned
            var frag,par=frag=document.createDocumentFragment();
            
            //Function to parse after a tag has closed
            function parse_e(){
                
                //If there is no string, no need to continue
                if(str){
                
                    //Execute a regular expression, then remove it from the string
                    var ret=r_end.exec(str);
                    str=str.replace(r_end,"")
                    
                    //If there is text, append it
                    ret[1]&&par.appendChild(document.createTextNode(ret[1]))
                    
                    //go up to the previous parent
                    par=par.parentNode||frag;
                    
                    //Parse the next part
                    parse_s();
                }
            }
            
            
            //Parse before a tag starts
            function parse_s(ret,elem,a,e){
                        
                        //if there is even a string and the regular expression comes up with something
                        if(str&&(ret=r_start.exec(str))){
                            
                            //remove that regular expression from the string
                            str=str.replace(r_start,"")
                            
                            //If there is text, append it
                            ret[1]&&par.appendChild(document.createTextNode(ret[1]))
                            
                            //If there is a tag
                            if(ret[2]){
                                
                                //Create and append an element with the tag
                                elem=par.appendChild(document.createElement(ret[2]))
                                
                                //assign a variable to the attribute section of results
                                a=ret[3]
                                
                                //While there is still an attribute
                                while(e=r_attr.exec(a)){
                                    
                                    //Remove it
                                    a=a.replace(r_attr,"");
                                    
                                    //And set it to the element
                                    e[1]?elem.setAttribute(e[1],e[2]||e[3]):elem.setAttribute(e[4],e[4])
                                }
                               
                            }
                            
                            //If the element is not unary, make it the new parent
                            if(!ret[4]){
                                par=elem;
                            }
                            
                            //If an end is in sight, parse that, otherwise parse a new element
                            r_end.test(str)?parse_e():parse_s();
                            
                        }
            }
            
            //begin the process
            parse_s()
            return (cache[str]=frag).cloneNode(true);
        }
    
    })(document,
       //r_start:
       /^([^<]*)(?:<(\w+)\s*((?:\s*\w+\s*(?:=\s*(?:'[^']*'|"[^"]*"))?)*)\s*(\/?)>)?/,
       
       //r_end:
       /\s*(\w+)\s*=\s*(?:'([^']*)'|"([^"]*)")|\s*(\w+)/,
       
       //r_attr:
       /^([^<]*)<\/(\w+)>/,
       
       //cache:
       {});