jquery: fill in text box (min of 5 characters) and will tick checkbox

I have a checkbox which i would like to check if the user fills in the text box that follows it. This must be a min of 5 chara开发者_开发百科cters for it to check the checkbox.

<input type="checkbox" id="olt3" name="olt3" <?php if (!empty($mychecklist->pro)) echo 'checked' ?>> 

<input type="text" id="pro" name="pro" value="<?php echo $mychecklist->pro?>">Please supply your ID

thanks in advance for any help.

Live Demo

Basically you just need to check the length of the input on keyup, if it meets your criteria use prop to set the checked property to true.

$('#pro').keyup(function(){
    if(this.value.length > 4){
        $('#olt3').prop('checked', true);
    }else{
        $('#olt3').prop('checked', false);
    }
});

I thinks this will do the trick:

$("#pro").bind("keyup", function(){
    var checked = ( $(this).val().length >= 5 );
    $("#olt3").attr("checked", checked);
});

http://jsfiddle.net/aalouv/S7cNM/

$(document).ready(function() {
   $("pro").keypress(function()
   {
      $('#olt3').checked =  $(this).val().length >=5 ? true : false;
   });
});

I hope this helps

First get the length of the text in the input field $("#pro").val().length, if the length is greater or equal to 5, than check the checkbox $("#olt3").prop("checked", true).

    $("input").keyup(function () {
      var length = $("#pro").val().length;
      if(length >= 5){
         $("#olt3").prop("checked", true);
      }
    }).keyup();