javascript 字符串 String

const dirName = Config.APP_Course_New;
let index = Config.APP_Course_New.lastIndexOf('/');
if (index !== -1)
{
    dirName = dirName.substring(index+1);
}
index = dirName.lastIndexOf(".");
dirName = dirName.substring(0,index);
console.log('dirName dirName ' +dirName);

http://www.w3school.com.cn/jsref/jsref_obj_string.asp