window.alert = alert;
//重写alert
function alert (data, callback) { //回调函数
    var alert_bg = document.createElement(‘div‘),
    alert_box = document.createElement(‘div‘),
        alert_text = document.createElement(‘div‘),
        alert_btn = document.createElement(‘div‘),
        textNode = document.createTextNode(data ? data : ‘‘),
        btnText = document.createTextNode(‘确 定‘);

    // 控制样式
    css(alert_bg, {
        ‘position‘: ‘fixed‘,
        ‘top‘: ‘0‘,
        ‘left‘: ‘0‘,
        ‘right‘: ‘0‘,
        ‘bottom‘: ‘0‘,
        ‘background-color‘: ‘rgba(0, 0, 0, 0.1)‘,
        ‘z-index‘: ‘999999999‘
    });

    css(alert_box, {
        ‘width‘: ‘270px‘,
        ‘max-width‘: ‘90%‘,
        ‘font-size‘: ‘16px‘,
        ‘text-align‘: ‘center‘,
        ‘background-color‘: ‘#fff‘,
        ‘border-radius‘: ‘15px‘,
        ‘position‘: ‘absolute‘,
        ‘top‘: ‘50%‘,
        ‘left‘: ‘50%‘,
        ‘transform‘: ‘translate(-50%, -50%)‘
    });

    css(alert_text, {
        ‘padding‘: ‘30px 15px‘,
        ‘border-bottom‘: ‘1px solid #ddd‘
    });

    css(alert_btn, {
        ‘padding‘: ‘10px 0‘,
        ‘color‘: ‘#007aff‘,
        ‘font-weight‘: ‘600‘,
        ‘cursor‘: ‘pointer‘
    });

    // 内部结构套入
    alert_text.appendChild(textNode);
    alert_btn.appendChild(btnText);
    alert_box.appendChild(alert_text);
    alert_box.appendChild(alert_btn);
    alert_bg.appendChild(alert_box);

    // 整体显示到页面内
    document.getElementsByTagName(‘body‘)[0].appendChild(alert_bg);

    // 确定绑定点击事件删除标签
    alert_btn.onclick = function () {
        alert_bg.parentNode.removeChild(alert_bg);
        if (typeof callback === ‘function‘) {
            callback(); //回调
        }
    }
}
function css (targetObj, cssObj) {
    var str = targetObj.getAttribute("style") ? targetObj.getAttribute(‘style‘) : ‘‘;
    for (var i in cssObj) {
        str += i + ‘:‘ + cssObj[i] + ‘;‘;
    }
    targetObj.style.cssText = str;
}