Check First Char In String

Question

I have input-box. I'm looking for a way to fire-up alert() if first character of given string is equal to '/'...

var scream = $( '#screameria input' ).val();

if ( scream.charAt( 0 ) == '/' ) {

  alert( 'Boom!' );

}

It's my code at the moment. It doesn't work and I think that it's because that browser doesn't know when to check that string... I need that alert whenever user inputs '/' as first character.

Naftali · Accepted Answer · 2011-06-14 18:38:02Z

26

Try this out:

$( '#screameria input' ).keyup(function(){ //when a user types in input box
    var scream = this.value;
    if ( scream.charAt( 0 ) == '/' ) {

      alert( 'Boom!' );

    }
})

Fiddle: http://jsfiddle.net/maniator/FewgY/

answered Jun 14, 2011 at 18:38

Naftali

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8 Comments

daGrevis Over a year ago

There are one unexpected bug. When alert() is fired-up, user will try to close it with "Enter", but that will call alert() again. How would you solve this?

Naftali Over a year ago

well what you can do is clear out the value before the Boom so they submit nothing: this.value = ''

Naftali Over a year ago

@daGrevis -- #1 use jsFiddle. #2, the isFired variable is not in the global scope

daGrevis Over a year ago

@Neal But I use it only in that anonymous function... so does it matters? P.S. I will use jsFiddle. ;)

Naftali Over a year ago

yes it only exists in that anon. and never at any other point. it disappears. -- poof --

|

maerics · Accepted Answer · 2011-06-14 18:46:54Z

4

You need to add a keypress (or similar) handler to tell the browser to run your function whenever a key is pressed on that input field:

var input = $('#screameria input');
input.keypress(function() {
  var val = this.value;
  if (val && val.charAt(0) == '/') {
    alert('Boom!');
  }
});

edited Jun 14, 2011 at 18:46

answered Jun 14, 2011 at 18:39

maerics

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2 Comments

Naftali Over a year ago

Do not use input.val(), use either $(this).val() or this.value, you have no idea how many inputs there are.

maerics Over a year ago

@Neal, ha, true. I guess that's a sign that we're doing it right =)

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