function MyClass () {} MyClass.hasClassName = function(element, className) { if (!element) return; var elementClassName = element.className; if (elementClassName.length == 0) return false; //用正则表达式判断多个class之间是否存在真正的class（前后空格的处理） if (elementClassName == className || elementClassName.match(new RegExp("(^|\\s)" + className + "(\\s|$)"))) return true; return false; }; MyClass.addClassName = function(element, className) { if (!element) return; var elementClassName = element.className; if (elementClassName.length == 0) { element.className = elementClassName; return; } if (elementClassName == className || elementClassName.match(new RegExp("(^|\\s)" + className + "(\\s|$)"))) return; element.className = elementClassName + " " + className; }; MyClass.removeClassName = function(element, className) { if (!element) return; var elementClassName = element.className; if (elementClassName.length == 0) return; if(elementClassName == className) { element.className = ""; return; } if (elementClassName.match(new RegExp("(^|\\s)" + className + "(\\s|$)"))) element.className = elementClassName.replace((new RegExp("(^|\\s)" + className + "(\\s|$)"))," "); };