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Gal1

Global variable very basic

in Using jQuery • 6 years ago

Hello everyone,

I have a very basic question with global variable and Jquery.

Here i is a counter. I want to know its last value and keep it out of the function

<div class="aremplir">
</div>
<button type="button" id="ajouter">Ajouter</button>
<script type="text/javascript">
jQuery(function($){
var i = 0;
$('#ajouter').click(function(e){
e.preventDefault();
var content = "<div id='input_name"+i+"'><input type='text' /></div>";
i++;
$('.aremplir').append(content);
mon_dernier_i = i;
});
if(typeof mon_dernier_i !='undefined'){
console.log(mon_dernier_i);
}
});
</script>

it seems that mon_dernier_i is not defined : nothing happens. I thought that not declaring 'var' in the function would make 'mon_dernier_i' global but obviously I am wrong...

Can anyone explain it to me ?

Thank you very much

Replies(3)

jakecigar

Re: Global variable very basic

6 years ago

In the old days, not declaring a variable made it a global. Currently it makes you a bad programmer. In "strict" mode, it makes it an error. Declare your variables. Don’t be bad.

Line 17 of your code happens when the script is run. Line 14 happens much later, during a click.

You can’t access a value that hasn’t been set yet.

JΛ̊KE

Gal1

Re: Re: Global variable very basic

6 years ago

Thank you Jake for this answer.

I don't really know how I am going to deal with it (how can I keep the record of this out of the function ?), but thanks anyway, I understand better why it doesn't work

jakecigar

Re: Global variable very basic

6 years ago

i is already a semi-global variable. You can just use it any time you like.

You should pick a better name for this important variable. Maybe, numberOfInputs would be better.

You are building inputs with sequential ids. That’s not a good idea.

var content = "<div class=ajoute><input type='text' data-numero='"+ i +"' /></div>";

Stores the value of i with the input tag itself. (note the single quotes next to the double quotes.)

JΛ̊KE

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