Jquery: increase the current form input value with 1

I'm just trying to get a number from a hidden form input and plus 1 to that number 开发者_运维百科and then put that value to the incremented number.

Here is my code

jQuery('#add_slider_image').live('click', function() {

  var slideId = jQuery('#count-level').attr('value');
  jQuery('#count-level').attr('value',slideId+1);

});

What am I doing wrong? as it changes the value to 11 or even 111 depending on the amount of clicks. It needs to add the value with 1. like 1+1=2 not 11.

Thanks

its converting it to a string. make sure to do

var slideId = parseInt(jQuery('#count-level').attr('value'));

It sounds like the variable needs to be converted from string to integer. Not positive, but this may work:

change:

jQuery('#count-level').attr('value',slideId+1);

to:

jQuery('#count-level').attr('value',parseInt(slideId)+1);

More on jquery Integers and parsing numbers: http://docs.jquery.com/Types#Integer