Funny, I just made one of these. It is quite efficient because it compiles selectors. I don't know if it's IE6-compatible but it should be, I think. It supports CSS3 too - bonus points? :)
if(![].indexOf)Array.prototype.indexOf=function(a,i){i=i||0;while(i<this.length)if(this[i++]===a)return i-1;return-1};
String.prototype.startsWith=function(s){return this.length>=s.length&&this.substring(0,s.length)===s};
String.prototype.endsWith=function(s){return this.length>=s.length&&this.substring(this.length-s.length)===s};
var Sprint = {
Error: function(m) {
this.message = m;
this.toString = function() {
return this.message;
};
},
getAllElementsIn: function(element) {
var r = [];
var f = function recurse(l, arr) {
from(l).each(function(k, v) {
if(v.nodeType === 1) {
arr.push(v);
recurse(v, arr);
}
});
};
f(element, r);
return r;
},
getAllElements: function() {
return Sprint.getAllElementsIn(document.documentElement);
},
getSiblings: function(element) {
return element.parentNode ? from(element.parentNode).where(function(k, v) { return v.nodeType === 1; }).toArray() : [element];
},
getInfo: function(selector) {
var r = {ATTR: {}, CLASS: [], PSEUDO: []};
var quotes = '\'"', nestable = '(){}', inAttribute = false, escaped = false, currentQuotes = null, currentNested = [], nonchar = /^[^a-zA-Z0-9_\-]$/, lastSplitter = null, i = -1, c, s = '';
while(++i < selector.length) {
c = selector.charAt(i);
if(escaped) {
escaped = false;
} else if(c === '\\') {
escaped = true;
continue;
} else if(currentQuotes) {
if(currentQuotes === c) {
currentQuotes = null;
}
} else if(quotes.indexOf(c) > -1) {
currentQuotes = c;
} else if(currentNested.length) {
if(nestable.indexOf(currentNested[currentNested.length - 1]) + 1 === nestable.indexOf(c)) {
currentNested.pop();
}
} else if(nestable.indexOf(c) > -1) {
currentNested.push(c);
} else if(nonchar.test(c)) {
if(lastSplitter) {
switch(lastSplitter) {
case '#':
r.ID = s;
break;
case '.':
r.CLASS.push(s);
break;
case '[':
case ',':
if(inAttribute) {
var j;
if((j = s.indexOf('=')) > -1) {
r.ATTR[s.substring(0, j)] = s.substring(j + 1);
} else {
r.ATTR[s] = true;
}
}
break;
case ':':
r.PSEUDO.push(s);
break;
}
} else {
r.TAG = s;
}
if(c === ']') {
inAttribute = false;
} else if(c === '[') {
inAttribute = true;
}
lastSplitter = c;
s = '';
continue;
}
s += c;
}
if(lastSplitter) {
switch(lastSplitter) {
case '#':
r.ID = s;
break;
case '.':
r.CLASS.push(s);
break;
case '[':
case ',':
if(inAttribute) {
var j;
if((j = s.indexOf('=')) > -1) {
r.ATTR[s.substring(0, j)] = s.substring(j + 1);
} else {
r.ATTR[s] = true;
}
}
break;
case ':':
r.PSEUDO.push(s);
break;
}
} else {
r.TAG = s;
}
return r;
},
compileSingle: function(info) {
var f = 'var t=l.nodeName?l.nodeName.toLowerCase():"",i=l.id?l.id.toLowerCase():"",c=l.className?" "+l.className.toLowerCase()+" ":"",s=Sprint.getSiblings(l),ss=from(s).where(function(k,v){return v.nodeName?v.nodeName.toLowerCase()===t:false;}).toArray(),si=s.indexOf(l),ssi=ss.indexOf(l);return ';
if(info.TAG && info.TAG !== '*') {
f += 't===\'' + info.TAG.toLowerCase().replace(/[\\']/g, function(x) { return '\\' + x; }) + '\'&&';
}
if(info.ID) {
f += 'i===\'' + info.ID.toLowerCase().replace(/[\\']/g, function(x) { return '\\' + x; }) + '\'&&';
}
if(info.CLASS) {
for(var i = 0; i < info.CLASS.length; i++) {
f += 'c.indexOf(\' ' + info.CLASS[i].toLowerCase() + ' \')>-1&&';
}
}
if(info.PSEUDO) {
for(var i = 0; i < info.PSEUDO.length; i++) {
var p = info.PSEUDO[i], j, v = '';
if((j = p.indexOf('(')) > -1) {
v = p.substring(j + 1, p.length - 1);
p = p.substring(0, j);
}
switch(p) {
case 'first-child':
f += '!si';
break;
case 'first-of-type':
f += '!ssi';
break;
case 'nth-child':
// TODO: Implement all nth-*** selectors.
break;
case 'nth-of-type':
break;
case 'last-child':
f += 'si===s.length-1';
break;
case 'last-of-type':
f += 'ssi===ss.length-1';
break;
case 'nth-last-child':
break;
case 'nth-last-of-type':
break;
case 'only-child':
f += 's.length===1';
break;
case 'only-of-type':
f += 'ss.length===1';
break;
case 'disabled':
f += 'l.disabled';
break;
case 'enabled':
f += '!l.disabled';
break;
case 'checked':
f += 'l.checked';
break;
case 'empty':
f += '!l.childNodes.length'; // TODO: Maybe restrict to elements (t 1) only?
break;
case 'not':
f += '!Sprint.isMatch(\'' + v.replace(/\\'/g, function(x) { return '\\' + x; }) + '\')(0,l)';
break;
default:
throw new Sprint.Error("Unrecognized pseudo-class \"" + p + "\".");
}
f += '&&';
}
}
if(info.ATTR) {
from(info.ATTR).each(function(k, v) {
var c = k.charAt(k.length - 1);
f += 'l.getAttribute(\'' + ('$^*~|'.indexOf(c) > -1 ? k.substring(0, k.length - 1) : k).replace(/\\'/g, function(x) { return '\\' + x; }) + '\')';
if(typeof v === 'string') {
v = v.replace(/\\'/g, function(x) { return '\\' + x; });
switch(c) {
case '$':
f += '.endsWith(\'' + v + '\')';
break;
case '^':
f += '.startsWith(\'' + v + '\')';
break;
case '*':
f += '.indexOf(\'' + v + '\')+1';
break;
case '~':
f += '.split(\' \').indexOf(\'' + v + '\')+1';
break;
case '|':
f += '.split(\'-\').indexOf(\'' + v + '\')+1';
break;
default:
f += '===\'' + v + '\'';
}
}
f += '&&';
});
}
if(f.substring(f.length - 2) !== '&&') {
// It matches anything.
f = 'return true ';
}
return new Function(['l'], f.substring(0, f.length - 2) + ';');
},
compileTree: function(selector) {
var t = Sprint.tokenizeSelector(selector), i = -1, j, splitters = ', >~+';
while(++i < t.length) {
if(splitters.indexOf(t[i]) > -1) {
j = i;
while(--j >= 0 && t[j] === ' ') t[j] = null;
j = i;
while(++j < t.length && t[j] === ' ') t[j] = null;
}
}
return from(t).where().select(function(k, v) {
return k % 2 ? v : Sprint.compileSingle(Sprint.getInfo(v));
}).toArray();
},
matchSingleTree: function(element, tree) {
if(!tree.length) {
return true;
}
if(!tree[tree.length - 1](element)) {
return false;
}
for(var i = tree.length - 3; i >= 0; i -= 2) {
switch(tree[i + 1] || ' ') {
case ' ':
while(true) {
if(!(element = element.parentNode)) {
return false;
}
if(tree[i](element)) {
break;
}
}
break;
case '>':
if(!(element = element.parentNode) || !tree[i](element)) {
return false;
}
break;
case '+':
while(true) {
if(!(element = element.previousSibling)) {
return false;
}
if(element.nodeType === 1) {
if(!tree[i](element)) {
return false;
} else {
break;
}
}
}
break;
case '~':
while(true) {
if(!(element = element.previousSibling)) {
return false;
}
if(tree[i](element)) {
break;
}
}
break;
}
}
return true;
},
matchTree: function(element, tree) {
var c = [];
for(var i = 0; i < tree.length; i++) {
if(tree[i] === ',') {
if(Sprint.matchSingleTree(element, c)) {
return true;
}
c = [];
} else {
c.push(tree[i]);
}
}
return Sprint.matchSingleTree(element, c);
},
tokenizeSelector: function(selector) {
var quotes = '\'"', nestable = '(){}[]', escaped = false, currentQuotes = null, currentNested = [], tokens = [], splitters = ', >~+', i = -1, c, s = '';
while(++i < selector.length) {
c = selector.charAt(i);
if(escaped) {
escaped = false;
} else if(c === '\\') {
escaped = true;
continue;
} else if(currentQuotes) {
if(currentQuotes === c) {
currentQuotes = null;
}
} else if(quotes.indexOf(c) > -1) {
currentQuotes = c;
} else if(currentNested.length) {
if(nestable.indexOf(currentNested[currentNested.length - 1]) + 1 === nestable.indexOf(c)) {
currentNested.pop();
}
} else if(nestable.indexOf(c) > -1) {
currentNested.push(c);
} else if(splitters.indexOf(c) > -1) {
tokens.push(s);
tokens.push(c);
s = '';
continue;
}
s += c;
}
tokens.push(s);
return tokens;
},
isMatch: function(selector) {
var f = Sprint.compileTree(selector);
return function(key, element) {
return Sprint.matchTree(element, f);
};
},
select: function(selector) {
return from(Sprint.getAllElements()).where(Sprint.isMatch(selector)).toArray();
},
selectIn: function(selector, element) {
return from(Sprint.getAllElementsIn(element)).where(Sprint.isMatch(selector)).toArray();
}
};
function from(x) {
if(!x) {
throw new Sprint.Error("null or undefined passed to Sprint:from().");
}
var r = {
keys: [],
values: []
};
if(x.length) {
for(var i = 0; i < x.length; i++) {
r.keys.push(i);
r.values.push(x[i]);
}
} else if(x.childNodes) {
return from(x.childNodes);
} else {
for(var y in x) {
if(x.hasOwnProperty(y)) {
r.keys.push(y);
r.values.push(x[y]);
}
}
}
r.length = r.keys.length;
r.where = function(f) {
if(f) {
if(typeof f === 'string') return this.where(new Function(['k', 'v'], 'return ' + f + ';'));
var r = {};
for(var i = 0; i < this.length; i++) {
if(f(this.keys[i], this.values[i])) {
r[this.keys[i]] = this.values[i];
}
}
return from(r);
} else {
return this.where(function(k, v) { return v; });
}
};
r.select = function(f) {
var r = {};
for(var i = 0; i < this.length; i++) {
r[this.keys[i]] = f(this.keys[i], this.values[i]);
}
return from(r);
};
r.each = function(f) {
for(var i = 0; i < this.length; i++) {
f(this.keys[i], this.values[i]);
}
};
r.first = function() {
return this.values[0];
};
r.last = function() {
return this.values[this.length - 1];
};
r.splitBy = function(f) {
if(typeof f === 'function') {
var r = [], c = {};
for(var i = 0; i < this.length; i++) {
if(f(this.keys[i], this.values[i])) {
r.push(c);
c = {};
} else {
c[this.keys[i]] = this.values[i];
}
}
r.push(c);
return from(r);
} else {
return this.splitBy(function(x) { return x === f; });
}
};
r.limit = function(f) {
var r = {}, i = -1;
if(typeof f === 'function') {
while(++i < this.length && f(this.keys[i], this.values[i])) {
r[this.keys[i]] = this.values[i];
}
} else {
while(++i < Math.min(this.length, f)) {
r[this.keys[i]] = this.values[i];
}
}
return from(r);
};
r.after = function(f) {
var r = {}, i = -1;
if(typeof f === 'function') {
while(++i < this.length && !f(this.keys[i], this.values[i])) {
}
while(++i < this.length) {
r[this.keys[i]] = this.values[i];
}
} else {
if(f < this.length) {
i = f - 1;
while(++i < this.length) {
r[this.keys[i]] = this.values[i];
}
}
}
return from(r);
};
r.toArray = function() {
return this.values;
};
return r;
}
You use it like so:
Sprint.selectIn("mySelector", element);
Or
Sprint.select("mySelector")
. The code is 6.89KB minified and 2.26KB gzipped.
