SOURCE

function encodeToBase64(str) {  
    return window.btoa(unescape(encodeURIComponent(str))); // 用于处理特殊字符  
}  
  
var str = {"method":"GET","timestamp":1714959030876,"url":"https://interactive.hn0746.com/activities/appColumnConfig/getColumnsOfAvailableModel?appInfoId\u003d596\u0026appModelId\u003d298"};  
var base64 = encodeToBase64(JSON.stringify(str));  
console.log(base64); // 输出类似 "SGVsbG8sIFdvcmxkIQ=="