javascript - Checking multiple prices, increase total price label -

i'm attempting add total price on website whenever user clicks on checkbox - using jquery, recieving $nan when add results. alert box near end of script showing weird results (leading 0s, i'm not sure why)

here's current code:

$("#additionaloffers").bind("click", "input:checkbox", function () {                     var $items = $("#additionaloffers").find("input:checkbox:checked");                     var $total = $("#totalprice");                     var cur_total = 0;                      $items.each(function () {                         var $this = $(this);                         var target = $("span[class='" + $this.attr("id") + "']");                         var item_value = +target.text()                          cur_total += item_value;                         alert(cur_total);                     });                      $total.html("$" + cur_total);                 }); 

because i'm using .net, markup looks this:

<asp:checkbox id="checkbox7" cssclass="label-for-check" text="lease/sales consultation" runat="server" /> <span class="checkbox7">75</span> <br /> <asp:checkbox id="checkbox1" cssclass="label-for-check" text="lease review advisor" runat="server" /> <span class="checkbox1">50</span> <br /> <asp:checkbox id="checkbox2" cssclass="label-for-check" text="starter package" runat="server" /> <span class="checkbox2">25</span> <br /> 

i feel there silly reason isn't working. appreciated!

the reason you're using asp.net, ids dynamically generated , $this.attr("id") returns different value span class in

var target = $("span[class='" + $this.attr("id") + "']"); 

for example, when span class checkbox7, $this.attr("id") returns {prefix}checkbox7.

solution 1: replace line with:

var target = $this.next(); 

solution 2:

in case need find class, use attribute other id. in code-behind:

checkbox7.attributes["myspanclass"] = "checkbox7"; checkbox1.attributes["myspanclass"] = "checkbox1"; checkbox2.attributes["myspanclass"] = "checkbox2"; 

and replace line with:

 var target = $("span[class='" + $this.attr("myspanclass") + "']");