diff --git a/.gitignore b/.gitignore
index 697f01c..7837f62 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 /lib/index.js
 /build/
 /node_modules/
+
+*.swp
diff --git a/lib/CSSValue.js b/lib/CSSValue.js
new file mode 100644
index 0000000..f2facb1
--- /dev/null
+++ b/lib/CSSValue.js
@@ -0,0 +1,43 @@
+//.CommonJS
+var CSSOM = {};
+///CommonJS
+
+
+/**
+ * @constructor
+ * @see http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSValue
+ *
+ * TODO: add if needed
+ */
+CSSOM.CSSValue = function CSSValue() {
+};
+
+CSSOM.CSSValue.prototype = {
+	constructor: CSSOM.CSSValue,
+
+	// @see: http://www.w3.org/TR/DOM-Level-2-Style/css.html#CSS-CSSValue
+	set cssText() {
+		var name = this._getConstructorName();
+
+		throw new Exception('DOMException: property "cssText" of "' + name + '" is readonly!');
+	},
+
+	get cssText() {
+		var name = this._getConstructorName();
+
+		throw new Exception('getter "cssText" of "' + name + '" is not implemented!');
+	},
+
+	_getConstructorName: function() {
+		var s = this.constructor.toString(),
+				c = s.match(/function\s([^\(]+)/),
+				name = c[1];
+
+		return name;
+	}
+};
+
+
+//.CommonJS
+exports.CSSValue = CSSOM.CSSValue;
+///CommonJS
diff --git a/lib/CSSValueExpression.js b/lib/CSSValueExpression.js
new file mode 100644
index 0000000..b6d4756
--- /dev/null
+++ b/lib/CSSValueExpression.js
@@ -0,0 +1,344 @@
+//.CommonJS
+var CSSOM = {
+	CSSValue: require('./CSSValue').CSSValue
+};
+///CommonJS
+
+
+/**
+ * @constructor
+ * @see http://msdn.microsoft.com/en-us/library/ms537634(v=vs.85).aspx
+ *
+ */
+CSSOM.CSSValueExpression = function CSSValueExpression(token, idx) {
+	this._token = token;
+	this._idx = idx;
+};
+
+CSSOM.CSSValueExpression.prototype = new CSSOM.CSSValue;
+CSSOM.CSSValueExpression.prototype.constructor = CSSOM.CSSValueExpression;
+
+/**
+ * parse css expression() value
+ *
+ * @return {Object}
+ *				 - error:
+ *				 or
+ *				 - idx:
+ *				 - expression:
+ *
+ * Example:
+ *
+ * .selector {
+ *		zoom: expression(documentElement.clientWidth > 1000 ? '1000px' : 'auto');
+ * }
+ */
+CSSOM.CSSValueExpression.prototype.parse = function() {
+	var token = this._token,
+			idx = this._idx;
+
+	var character = '',
+			expression = '',
+			error = '',
+			info,
+			paren = [];
+
+
+	for (; ; ++idx) {
+		character = token.charAt(idx);
+
+		// end of token
+		if (character == '') {
+			error = 'css expression error: unfinished expression!';
+			break;
+		}
+
+		switch(character) {
+			case '(':
+				paren.push(character);
+				expression += character;
+				break;
+
+			case ')':
+				paren.pop(character);
+				expression += character;
+				break;
+
+			case '/':
+				if (info = this._parseJSComment(token, idx)) { // comment?
+					if (info.error) {
+						error = 'css expression error: unfinished comment in expression!';
+					} else {
+						idx = info.idx;
+						// ignore the comment
+					}
+				} else if (info = this._parseJSRexExp(token, idx)) { // regexp
+					idx = info.idx;
+					expression += info.text;
+				} else { // other
+					expression += character;
+				}
+				break;
+
+			case "'":
+			case '"':
+				info = this._parseJSString(token, idx, character);
+				if (info) { // string
+					idx = info.idx;
+					expression += info.text;
+				} else {
+					expression += character;
+				}
+				break;
+
+			default:
+				expression += character;
+				break;
+		}
+
+		if (error) {
+			break;
+		}
+
+		// end of expression
+		if (paren.length == 0) {
+			break;
+		}
+	}
+
+	var ret;
+	if (error) {
+		ret = {
+			error: error
+		}
+	} else {
+		ret = {
+			idx: idx,
+			expression: expression
+		}
+	}
+
+	return ret;
+};
+
+
+/**
+ *
+ * @return {Object|false}
+ *          - idx:
+ *          - text:
+ *          or
+ *          - error:
+ *          or
+ *          false
+ *
+ */
+CSSOM.CSSValueExpression.prototype._parseJSComment = function(token, idx) {
+	var nextChar = token.charAt(idx + 1),
+			text;
+
+	if (nextChar == '/' || nextChar == '*') {
+		var startIdx = idx,
+				endIdx,
+				commentEndChar;
+
+		if (nextChar == '/') { // line comment
+			commentEndChar = '\n';
+		} else if (nextChar == '*') { // block comment
+			commentEndChar = '*/';
+		}
+
+		endIdx = token.indexOf(commentEndChar, startIdx + 1 + 1);
+		if (endIdx !== -1) {
+			endIdx = endIdx + commentEndChar.length - 1;
+			text = token.substring(idx, endIdx + 1);
+			return {
+				idx: endIdx,
+				text: text
+			}
+		} else {
+			error = 'css expression error: unfinished comment in expression!';
+			return {
+				error: error
+			}
+		}
+	} else {
+		return false;
+	}
+};
+
+
+/**
+ *
+ * @return {Object|false}
+ *					- idx:
+ *					- text:
+ *					or 
+ *					false
+ *
+ */
+CSSOM.CSSValueExpression.prototype._parseJSString = function(token, idx, sep) {
+	var endIdx = this._findMatchedIdx(token, idx, sep),
+			text;
+
+	if (endIdx === -1) {
+		return false;
+	} else {
+		text = token.substring(idx, endIdx + sep.length);
+
+		return {
+			idx: endIdx,
+			text: text
+		}
+	}
+};
+
+
+/**
+ * parse regexp in css expression
+ *
+ * @return {Object|false}
+ *				 - idx:
+ *				 - regExp:
+ *				 or 
+ *				 false
+ */
+
+/*
+
+all legal RegExp
+ 
+/a/
+(/a/)
+[/a/]
+[12, /a/]
+
+!/a/
+
++/a/
+-/a/
+* /a/
+/ /a/
+%/a/
+
+===/a/
+!==/a/
+==/a/
+!=/a/
+>/a/
+>=/a/
+</a/
+<=/a/
+
+&/a/
+|/a/
+^/a/
+~/a/
+<</a/
+>>/a/
+>>>/a/
+
+&&/a/
+||/a/
+?/a/
+=/a/
+,/a/
+
+		delete /a/
+				in /a/
+instanceof /a/
+			 new /a/
+		typeof /a/
+			void /a/
+
+*/
+CSSOM.CSSValueExpression.prototype._parseJSRexExp = function(token, idx) {
+	var before = token.substring(0, idx).trimRight(),
+			legalRegx = [
+				/^$/,
+				/\($/,
+				/\[$/,
+				/\!$/,
+				/\+$/,
+				/\-$/,
+				/\*$/,
+				/\/\s+/,
+				/\%$/,
+				/\=$/,
+				/\>$/,
+				/\<$/,
+				/\&$/,
+				/\|$/,
+				/\^$/,
+				/\~$/,
+				/\?$/,
+				/\,$/,
+				/delete$/,
+				/in$/,
+				/instanceof$/,
+				/new$/,
+				/typeof$/,
+				/void$/,
+			];
+
+	var isLegal = legalRegx.some(function(reg) {
+		return reg.test(before);
+	});
+
+	if (!isLegal) {
+		return false;
+	} else {
+		var sep = '/';
+
+		// same logic as string
+		return this._parseJSString(token, idx, sep);
+	}
+};
+
+
+/**
+ *
+ * find next sep(same line) index in `token`
+ *
+ * @return {Number}
+ *
+ */
+CSSOM.CSSValueExpression.prototype._findMatchedIdx = function(token, idx, sep) {
+	var startIdx = idx,
+			endIdx;
+
+	var NOT_FOUND = -1;
+
+	while(true) {
+		endIdx = token.indexOf(sep, startIdx + 1);
+
+		if (endIdx === -1) { // not found
+			endIdx = NOT_FOUND;
+			break;
+		} else {
+			var text = token.substring(idx + 1, endIdx),
+					matched = text.match(/\\+$/);
+			if (!matched || matched[0] % 2 == 0) { // not escaped
+				break;
+			} else {
+				startIdx = endIdx;
+			}
+		}
+	}
+
+	// boundary must be in the same line(js sting or regexp)
+	var nextNewLineIdx = token.indexOf('\n', idx + 1);
+	if (nextNewLineIdx < endIdx) {
+		endIdx = NOT_FOUND;
+	}
+
+
+	return endIdx;
+}
+
+
+
+
+//.CommonJS
+exports.CSSValueExpression = CSSOM.CSSValueExpression;
+///CommonJS
diff --git a/lib/parse.js b/lib/parse.js
index fbcdc76..ef68df7 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -11,14 +11,14 @@ CSSOM.parse = function parse(token) {
 	var i = 0;
 
 	/**
-	  "before-selector" or
-	  "selector" or
-	  "atRule" or
-	  "atBlock" or
-	  "before-name" or
-	  "name" or
-	  "before-value" or
-	  "value"
+		"before-selector" or
+		"selector" or
+		"atRule" or
+		"atBlock" or
+		"before-name" or
+		"name" or
+		"before-value" or
+		"value"
 	*/
 	var state = "before-selector";
 
@@ -220,15 +220,28 @@ CSSOM.parse = function parse(token) {
 
 		case '(':
 			if (state === 'value') {
-				index = token.indexOf(')', i + 1);
-				if (index === -1) {
-					parseError('Unmatched "("');
+				// ie css expression mode
+				if (buffer.trim() == 'expression') {
+					var info = (new CSSOM.CSSValueExpression(token, i)).parse();
+
+					if (info.error) {
+						parseError(info.error);
+					} else {
+						buffer += info.expression;
+						i = info.idx;
+					}
+				} else {
+					index = token.indexOf(')', i + 1);
+					if (index === -1) {
+						parseError('Unmatched "("');
+					}
+					buffer += token.slice(i, index + 1);
+					i = index;
 				}
-				buffer += token.slice(i, index + 1);
-				i = index;
 			} else {
 				buffer += character;
 			}
+
 			break;
 
 		case "!":
@@ -341,4 +354,5 @@ CSSOM.CSSFontFaceRule = require("./CSSFontFaceRule").CSSFontFaceRule;
 CSSOM.CSSStyleDeclaration = require('./CSSStyleDeclaration').CSSStyleDeclaration;
 CSSOM.CSSKeyframeRule = require('./CSSKeyframeRule').CSSKeyframeRule;
 CSSOM.CSSKeyframesRule = require('./CSSKeyframesRule').CSSKeyframesRule;
+CSSOM.CSSValueExpression = require('./CSSValueExpression').CSSValueExpression;
 ///CommonJS
diff --git a/spec/CSSValueExpression.spec.js b/spec/CSSValueExpression.spec.js
new file mode 100644
index 0000000..7ace60b
--- /dev/null
+++ b/spec/CSSValueExpression.spec.js
@@ -0,0 +1,51 @@
+describe('CSSOM', function() {
+describe('CSSValueExpression', function() {
+
+	var END = '__EOL__';
+
+
+	var cssExpressionValue = [
+"(function(hash){",
+"	if (!hash.match(/#[0-9a-f]{3,6}/g)) {",
+"		hash = hash.substr(1);",
+"		if (!hash) {",
+"			hash = '#ccc';",
+"		}",
+"	}",
+
+"	var n1 = 4/5;",
+
+"	// hello line comment",
+
+"	var n2 = 5/6;",
+
+"	var r1 = /hello ( /img;",
+
+"	// hello line comment",
+
+"	/* hello block comment */",
+
+"	return hash;",
+"}(location.hash))",
+
+END
+
+	].join('\n');
+
+
+
+	given(cssExpressionValue, function(token) {
+		var i = 0;
+
+		var info = (new CSSOM.CSSValueExpression(token, i)).parse();
+
+		expect(info.idx).toBeDefined();
+
+		var end = token.substr(info.idx + 1);
+		end = end.trim();
+		expect(end).toBe(END);
+	});
+
+
+});
+});
diff --git a/spec/index.html b/spec/index.html
index b66aa53..455d3ed 100644
--- a/spec/index.html
+++ b/spec/index.html
@@ -21,6 +21,7 @@
 	<script src="CSSStyleRule.spec.js"></script>
 	<script src="CSSStyleDeclaration.spec.js"></script>
 	<script src="CSSStyleSheet.spec.js"></script>
+	<script src="CSSValueExpression.spec.js"></script>
 	<script>
 	var htmlReporter = new jasmine.HtmlReporter();
 	var jasmineEnv = jasmine.getEnv();
diff --git a/src/files.js b/src/files.js
index 94c55b8..3829ed3 100644
--- a/src/files.js
+++ b/src/files.js
@@ -10,6 +10,8 @@ exports.files = [
 	"CSSStyleSheet",
 	"CSSKeyframesRule",
 	"CSSKeyframeRule",
+	"CSSValue",
+	"CSSValueExpression",
 	"parse",
 	"clone"
 ];