A simple DOM query library

SexyDollar.js

/*

  SexyDollar library by Witiko
  
    Function $()
      1st argument: "tagName", "#id", ".className", "tagName.className", "@name", "tagName@name"  
      2nd argument: parentElement (optional)

*/

var $ = (function(getElementsByClassName) {
  return function(query, element) {
    var func = query?(/#|\.|@/.exec(query) || [])[0]:null,
        index = query?query.indexOf(func):-1,
        tempArray, tempString, i;
    if(!query || !query.length) query = "*";
    if(!element) element = document;
    else if(!(element.length || (typeof HTMLElement === "object"?element instanceof HTMLElement:typeof element === "object" && (element.nodeType === 1 || element.nodeType ===  9) && typeof element.nodeName === "string" && element.hasChildNodes())))
      return func==="#"?null:[];
    switch(func) {
      case ".": 
        if(index === 0) {
          return element.getElementsByClassName?
            element.getElementsByClassName(query.substr(1)):
            getElementsByClassName(query.substr(1), false, element);
        } else {
          if(element.getElementsByClassName) {
            tempArray = [element.getElementsByClassName(query.substr(index + 1)),[]];
            tempString = new RegExp(query.substr(0,index), "i");
            for(i = 0; tempArray[0][i]; i++) {
              if(tempString.test(tempArray[0][i].tagName)) tempArray[1].push(tempArray[0][i]);
            }
            return tempArray[1];
          } else {
            return getElementsByClassName(query.substr(index + 1), query.substr(0,index), element);
          }
        }
      case "@":
        if(index === 0) {
          return element.getElementsByName(query.substr(1));
        } else {
          tempArray = [element.getElementsByName(query.substr(index + 1)),[]];
          tempString = new RegExp(query.substr(0,index), "i");
          for(i = 0; tempArray[0][i]; i++) {
            if(tempString.test(tempArray[0][i].tagName)) tempArray[1].push(tempArray[0][i]);
          }
          return tempArray[1];
        }
      case "#":
        return (element.getElementById?element:document).getElementById(query.substr(index + 1));
      default:
        return element.getElementsByTagName(query);
    }
  }
})(function(className, tag, elm) {
  var testClass = new RegExp("(^|\\s)" + className + "(\\s|$)"),
	    tag = tag || "*",
	    elm = elm || document,
	    elements = (tag === "*" && elm.all)? elm.all : elm.getElementsByTagName(tag),
	    returnElements = [],
	    current,
	    length = elements.length;
	for(var i=0; i<length; i++){
		current = elements[i];
		if(testClass.test(current.className)){
			returnElements.push(current);
		}
	}
	return returnElements;
});