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.

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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);
    }
});

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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/

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

I hope this helps

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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();