JQuery if input starts with a value

Question

I am managing to check the value inside a postcode input field using the following:

html:

<input type="text" class="cart-postcode2" size="10" tabindex="22">

JQuery:

$('.cart-postcode2').keyup(function(){
    var value = $(this).val();
    if (value.indexOf('BT') >= 0) {
        alert("is ireland");
    }
})

This is working great however I want it to only alert if it starts with BT and does not contain BT in any part of the value, does anyone know if this is possible?

So typing BT2 9NH will alert "Ireland" but typing OX2 8BT will not

possible duplicate of [JavaScript - check if string starts with](http://stackoverflow.com/questions/15310917/javascript-check-if-string-starts-with) — Felix Kling, Jul 25 '13 at 15:22
possible duplicate of [Javascript StartsWith](http://stackoverflow.com/questions/646628/javascript-startswith) — Ian, Jul 25 '13 at 15:22
Do you want the alert to on each key typed after BT is found or only once when it's first encountered? — Kevin Le - Khnle, Jul 25 '13 at 15:23
The proper way for us is to rollback such edits. Proper way for you is to delete the question (which is quite unfair to @Adil). Please do not edit questions this way. Thanks! — TLama, Jan 23 '14 at 09:54

score 15 · Answer 1 · answered Jul 25 '13 at 15:19

15

You can check if string starts with BT, as indexOf() will give index zero if value stats with BT

$('.cart-postcode2').keyup(function(){
    var value = $(this).val();
    if (value.indexOf('BT') == 0) {
      alert("is ireland");
    }
})

answered Jul 25 '13 at 15:19

Adil

139,325
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score 0 · Answer 2 · edited Jan 17 '17 at 16:28

0

a regex solution:

$('.cart-postcode2').keyup(function(){
    var value = $(this).val();
    if (value.match(/^BT/)) {
      alert("is ireland");
    }
})

edited Jan 17 '17 at 16:28

jmarkmurphy

9,829
28
51

answered Jul 25 '13 at 15:22

Plato

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1

The regex solution was wrong - it didn't have the `^` to make sure it **started with** "BT" – Ian Jul 25 '13 at 15:24
yup, i edited it, but then it got deleted... can't hurt to have multiple options available for future ppl finding the thread tho :) – Plato Jul 25 '13 at 15:25

JQuery if input starts with a value

2 Answers2