I have an error - alert is not a function

JavaScript
1

var tweet = prompt(“Compose your tweet:”);
var tweetUnder140 = tweet.slice(0.140);
alert(tweetUnder140);

I’m trying to push this code and i get the same error and i don’t know why .

2

The syntax for slice() uses a comma to separate start and end indexes, not a dot.

3

where are you running this code? alert works if you are creating an html page, not if it’s a JS only enviroment