I write this code for checking:
var num = $("#knum").val();
        if (isNaN(parseInt(num))) {
            $("#errorknum").html("Please define a number.");
        }
        else {
            if (num < 1 | num > 249) {
                $("#errorkrnum").html("your number must be less then 249 and can be greater than 1");
            }
            else {
                $("#errorknum").html("");
            }
Everything is fine but, for example, when the user type 1242fdlfldsf means it is 1242 but she accept it. How can I dishandle this value by code like for example: 23232dkfj
 
     
    