What is JavaScript Strict Mode ?

Example 1 : strict

<script>     
       "use strict"
        let a = 20;
        console.log(a+80)
</script>
 

Example 2 : use strict with function

<script>     
 let b = 30;
  function myfunc(){
   
     let c  = 120
      console.log(b+c)
  }
  myfunc()
</script>