docs(readme): add doc

components/login/util.ts

@@ -13,15 +13,7 @@ export const validatePhoneNumber = (str: string) => {
 /** 获取 url 中的某个参数值 */
 export const getQueryVariable = (variable: string) => {
   if (typeof window === 'undefined') return false
-  const query = window.location.search.substring(1)
-  const vars = query.split('&')
-  for (let i = 0; i < vars.length; i++) {
-    const pair = vars[i].split('=')
-    if (pair[0] === variable) {
-      return pair[1]
-    }
-  }
-  return false
+  return new URLSearchParams(window.location.search).get(variable) || false
 }
 
 /** 加载飞书二维码 SDK */