what is the wrong in my code it showing error " Invalid left-hand side in assignment "?

Question

it is showing error Invalid left-hand side in assignment? what is wrong in this code can any once help ?

Answer 1

The problem is that you have expressions returning true, which you then attempt to assign values.

What you meant to do is:

var a = document.getElementById('number').value; 
switch (+a){
    case 1 : alert('enter one'); break;
    case 2 : alert('enter two'); break;
    case 3 : alert('enter three'); break;
    case 4 : alert('enter four'); break;
}

The switch statement handles the comparisons for you. case 1 is the case where a is equal to 1.

Also, you want to get the element with the id "number", and instead of switch(a), you want switch(+a).

Answer 2

Problem is with your JavaScript. Syntax for Switch case is wrong. This is how it should be:

switch(a) {
    case 1: alert("enter one");break;
    case 2: alert("enter two");break;
    case 3:  alert("enter three");break;
    case 4:  alert("enter four");break;
}

JavaScript documentation