Return GET parameters from URL
/**
* Return GET parameters from URL
* @param param
* @returns Object|string|null
*/
function $_GET(param) {
var vars = {};
window.location.href.replace(
/[?&]+([^=&]+)=?([^&]*)?/gi,
function (m, key, value) {
vars[key] = value !== undefined ? value : '';
}
);
if (vars === {} || vars.length === 0) {
return null;
} else if (param && (typeof param === 'string' || param instanceof String)) {
return vars[param] ? vars[param] : null;
}
return vars;
}