javascript 【封装AJAX】

post

function createXHR() {
    if (typeof XMLHttpRequest != 'undefined') {
        return new XMLHttpRequest();
    } else if (typeof ActiveXObject != 'undefined') {
        var version = [
                                    'MSXML2.XMLHttp.6.0',
                                    'MSXML2.XMLHttp.3.0',
                                    'MSXML2.XMLHttp'
        ];
        for (var i = 0; version.length; i ++) {
            try {
                return new ActiveXObject(version[i]);
            } catch (e) {
                //跳过
            }
        }
    } else {
        throw new Error('您的系统或浏览器不支持XHR对象！');
    }
}

/*
//POST请求
addEvent(document, 'click', function () {
    var xhr = createXHR();
    var url = 'demo.php?rand=' + Math.random();
    xhr.onreadystatechange = function () {
        if (xhr.readyState == 4) {
            if (xhr.status == 200) {
                alert(xhr.responseText);
            } else {
                alert('获取数据错误！错误代号：' + xhr.status + '，错误信息：' + xhr.statusText);
            }
        }
    };
    xhr.open('post', url, true);                            //第一步改为post
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');        //第三步，模拟表单提交
    xhr.send('name=Lee&age=100');            //第二步将名值对放入send方法里
});
*/

封装AJax

function createXHR() {
    if (typeof XMLHttpRequest != 'undefined') {
        return new XMLHttpRequest();
    } else if (typeof ActiveXObject != 'undefined') {
        var version = [
                                    'MSXML2.XMLHttp.6.0',
                                    'MSXML2.XMLHttp.3.0',
                                    'MSXML2.XMLHttp'
        ];
        for (var i = 0; version.length; i ++) {
            try {
                return new ActiveXObject(version[i]);
            } catch (e) {
                //跳过
            }
        }
    } else {
        throw new Error('您的系统或浏览器不支持XHR对象！');
    }
}