CODEWITHSUNDEEP
javascriptinputswitch-statement
Mislavoo7
Mislavoo7

Reputation: 697

html input type= "text" as a case for switch is undefined

I'm trying to use input type="number" and swich together. When I write the number 2 (or some other) in the input field and press button go I hope to get the output "something 2" but I get "undefined".

see my code for html:

<body>
<form>
    <input type="number" id="entr">
    <input type="button" onclick="func()" value="go">
</form>
<p5 id="demo"></p5>

and for js:

function func() {
var x;
var a = document.getElementById("entr").value;
switch (a) {
    case 0:
          x = "something 0";  
        break;
    case 1:
          x = "something 1";  
        break;
    case 2:
          x = "something 2";  
        break;
    case 3:
          x = "something 3";  
        break;

}
document.getElementById("demo").innerHTML = x;

}

When I use default in the switch it execute that code block but never one of the oder code. thanks for answer

Upvotes: 0

Views: 765

Answers (2)

Brian S
Brian S

Reputation: 5056

While your input type is "number", the Javascript still treats it as a string by default. (Note that you're free to type arbitrary text into your input field.) You have two options: you can switch on the string value...

    switch (a) {
        case "0":
              x = "something 0";  
            break;
        case "1":
              x = "something 1";  
            break;
        case "2":
              x = "something 2";  
            break;
        case "3":
              x = "something 3";  
            break;

    }

That works, but it would be better to parse the input string as a number...

    var a = parseInt(document.getElementById("entr").value);

The unary + operator could work as well, but is less robust than the parseInt function...

    var a = +document.getElementById("entr").value;

Upvotes: 2

Iłya Bursov
Iłya Bursov

Reputation: 24229

change

var a = document.getElementById("entr").value;

to

var a = parseInt(document.getElementById("entr").value, 10);

Upvotes: 1

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