根据参数名称获取url中的参数值

getParameterByName.js

// 获取query parameters
// https://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript
function getParameterByName(name, url) {
    if (!url) url = window.location.href;
    name = name.replace(/[\[\]]/g, '\\$&');
    var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, ' '));
}