W3school is a good learning website for beginners. The following content mainly describes and uses the API of the JavaScript Object. If you do not understand the content, you can easily view the required questions.
Javascript string object reference manual
Http://www.w3school.com.cn/js/jsref_obj_string.asp
Javascript date object reference manual
Http://www.w3school.com.cn/js/jsref_obj_date.asp
Javascript date object reference manual
Http://www.w3school.com.cn/js/jsref_obj_date.asp
Javascript array Object Reference Manual
Http://www.w3school.com.cn/js/jsref_obj_array.asp
Javascript Boolean Object Reference Manual
Http://www.w3school.com.cn/js/jsref_obj_boolean.asp
Reference manual for JavaScript math objects
Http://www.w3school.com.cn/js/jsref_obj_math.asp
Javascript Regexp Object Reference Manual
Http://www.w3school.com.cn/js/jsref_obj_regexp.asp
Javascript html dom object
Http://www.w3school.com.cn/js/js_obj_htmldom.asp