What to consider in JS switch

Today, when doing practice code, use the switch to judge the statement, the code is as follows

<script>
function Showuser (SSS) {    var shen=sss;    Alert (typeof SSS);    Switch (shen)      {case      1:        x= "Zhang San";        break;      Case 2:        x= "John Doe";        break;      Case 3:        x= "Wang er";        break;      Case 4:        x= "Chen";        break;      }    document.getElementById ("Mydiv"). Innerhtml=x;}

</script><form> Select a user:<select name= "users" onchange= "Showuser (this.value)" ><option Value= "1" >peter griffin</option><option value= "2" >lois griffin</option><option value= "3" >glenn quagmire</option><option value= "4" >joseph Swanson</option></select></form >

<div id= "Mydiv" ></div>

The code is simple, the user chooses to make a judgment, then in the Mydiv section to display the corresponding text. But how to test can not display properly, after the online review know, in the switch used in the "= = =" Judgment, that is, at the same time to judge the type of parameters, after the code can be modified to normal use.

The modified function code is as follows:

function Showuser (SSS) {    var shen=sss;    Alert (typeof SSS);    Switch (shen)      {case      "1":        x= "Today it ' s Monday";        break;      Case "2":        x= "Today it ' s Tuesday";        break;      Case "3":        x= "Today it ' s Wednesday";        break;      Case "4":        x= "Today it ' s Thursday";        break;      }    document.getElementById ("Mydiv"). Innerhtml=x;}

　　

What to consider in JS switch