javascript - Number value is getting changed in JS -

this question has answer here:

• what javascript's highest integer value number can go without losing precision? 18 answers
• is there limitation integer in javascript? [duplicate] 4 answers

this post id:

var postid = 47213486358396931; var postcomments = "comment"; 

adding in object

var param = {     "postid" : postid,     "postcomment":postcomments }  

if print param this. last digit of number changed 0. why getting this.

{"postid" : 47213486358396930, "postcomment": "comment"}