1.hasClass
function hasClass(el, cls) {
if (!el || !cls) return false;
if (cls.indexOf(' ') !== -1) throw new Error('className should not contain space.');
if (el.classList) {
return el.classList.contains(cls);
} else {
return (' ' + el.className + ' ').indexOf(' ' + cls + ' ') > -1;
}
};
2.addClass
addClass(el, cls) {
if (!el) return;
var curClass = el.className;
var classes = (cls || '').split(' ');
for (var i = 0, j = classes.length; i < j; i++) {
var clsName = classes[i];
if (!clsName) continue;
if (el.classList) {
el.classList.add(clsName);
} else if (!hasClass(el, clsName)) {
curClass += ' ' + clsName;
}
}
if (!el.classList) {
el.className = curClass;
}
};
3.removeClass
removeClass(el, cls) {
if (!el || !cls) return;
var classes = cls.split(' ');
var curClass = ' ' + el.className + ' ';
for (var i = 0, j = classes.length; i < j; i++) {
var clsName = classes[i];
if (!clsName) continue;
if (el.classList) {
el.classList.remove(clsName);
} else if (hasClass(el, clsName)) {
curClass = curClass.replace(' ' + clsName + ' ', ' ');
}
}
if (!el.classList) {
el.className = trim(curClass);
}
};
trim函数
const trim = function(string) {
return (string || '').replace(/^[\s\uFEFF]+|[\s\uFEFF]+$/g, '');
};
