Question

var len = 160 - $(this).val.length;

I get same value foreach key press on target input..

Answer 1

It’s because you are asking the length of the val function (which will always be 1), instead of calling it and asking the length of what it returns. Try this:

var len = 160 - $(this).val().length

To illustrate this on Stackoverflow that conveniantly uses jQuery. Observe what would happen if you did the following:

console.log( $("input").val )          // [function definition of val]
console.log( $("input").val() )        // "search"
console.log( $("input").val.length )   // 1
console.log( $("input").val().length ) // 6

So say we want to bind to the search box and log the number of characters that has been put into it we would do:

$("#search input").live("keyup", function(){
    console.log($(this).val().length);
})