strict mode in javascript

Something Like that:
strict mode

Without strict mode
For that you need to create first html code.

HTML

<p id="demo"></p>

After that add this JS code.

JS

var person;
persom = {};
document.getElementById('demo').innerHTML = (persom);

[codepen_embed height=”265″ theme_id=”0″ slug_hash=”VzBwpx” default_tab=”result” user=”pradeepanvi”]See the Pen without strict mode in javascript by Pradeep Kumar (@pradeepanvi) on CodePen.[/codepen_embed]

Now you can see

[object Object]

With strict mode
For that you need to create first html code.

HTML

<p id="demo"></p>

After that add this JS code.

JS

"use strict"; // for strict mode
var person;
persom = {};
document.getElementById('demo').innerHTML = (persom);

[codepen_embed height=”265″ theme_id=”0″ slug_hash=”OjwJpq” default_tab=”result” user=”pradeepanvi”]See the Pen strict mode in javascript by Pradeep Kumar (@pradeepanvi) on CodePen.[/codepen_embed]

Now you can see

There you can see anything because, because you can see persom is not defined error is showing.