CODEWITHSUNDEEP
javascript
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Reputation: 63

How to validate a string without Reg ex - Javascript

Im trying to finish up an assignment; here's what Im stuck at:

User input can only contain the following allowed characters

Note: You cannot make use of Reg Ex.

I can't really see another way of doing this without use of Reg Ex; Here what I've done so far...

function validate_name() {
   var name = document.getElementById("name").value;
   name = name.trim();
   for (i = 0;i < name.lenght; i++) {
      if (name.charAt(i) == a...I don't know what I'm doing

Upvotes: 0

Views: 54

Answers (2)

Guy
Guy

Reputation: 1597

You can do something like that:

var str = prompt('Enter input:');
var alphaExist = false;
var valid = true;
for (var i = 0; i < str.length; i++) {
    if ("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'-".indexOf(str.charAt(i)) == -1) {
        valid = false;
    }
    if ("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".indexOf(str.charAt(i)) > -1) {
        alphaExist = true;
    }
}
alert(valid && alphaExist ? 'Valid' : 'Invalid');

http://jsfiddle.net/4wwod65h/

Upvotes: 1

gor181
gor181

Reputation: 2068

Have a look at the keycode list at: http://www.cambiaresearch.com/articles/15/javascript-char-codes-key-codes

Do not use 

document.getElementById("name").value;

Rather parse an event triggered by keystrokes. You have a nice example of how to use this on MDN page: https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode

So combine the keycode list and the keyboard event to filter the keycodes you are interested in.

Hint: You are able to use a range as keycodes are bunch of numbers.

Upvotes: 0

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