Get a Variable from id input value

Question

i have input value = 99.

<input type="text" id="num" value="99" />

so i want use that number for my alert bootstrap. that number is not showing in my alert, it say "undefined"

my javascript :

<script>
var x = document.getElementById("num").value;
    $('#alert').html("<div class='alert alert-danger'>ur number : "+window["x"]+"</div>");
</script>

i have tried using window. but it say "undefined".

Be consistent and also use $("#num").val() and execute AFTER load: $(function() { $('#alert').html("<div class='alert alert-danger'>Your number : "+$("#num").val()+"</div>"); }); — mplungjan
– mplungjan, Commented Apr 6, 2017 at 6:17
@mplungjan, Whats wrong with document.getElementById("num").value? Just because OP tagged jQuery — Satpal
– Satpal, Commented Apr 6, 2017 at 6:18
For consistency's sake - because he on next line uses the jQuery. It makes the code harder to read. If I use jQuery, I only ever use stuff like this.id when I do not use jQuery — mplungjan
– mplungjan, Commented Apr 6, 2017 at 6:20

mplungjan · Accepted Answer · 2017-04-06 06:22:52Z

1

Use jQuery .val() method to be consistent.

<script>
var x = $("#num").val();
$('#alert').html("<div class='alert alert-danger'>ur number : "+ x +"</div>");
</script>

If you want to set value on page load use jQuery .ready method

<script>
$(document).ready(function(){
  var x = $("#num").val();
  $('#alert').html("<div class='alert alert-danger'>ur number : "+ x +"</div>");
});
</script>

edited Apr 6, 2017 at 6:22

mplungjan

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answered Apr 6, 2017 at 6:17

Mayur Patel

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2 Comments

Dragon Chs Over a year ago

it work sir using $("#num").val(); but not work if im using document.getElementById("num").val(); it will work too using `document.getElementById("num").value; $('#alert').html("<div class='alert alert-danger'>ur number : "+ x +"</div>");

Mayur Patel Over a year ago

Because .val() is for jquery and document.getElementById("num") is pure javascript

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