Question

I have some ajax onclick stuff that updates this line when the value is selected from the menu:

<li id="li_273" data-pricefield="special" data-pricevalue="0" >

The intention is to take the that value (data-pricevalue) and then multiple it by the amount that is entered from another input box. Here’s my function to try to make that happen:

$('#main_body').delegate('#element_240','keyup', function(e){

var temp = $(this).attr("id").split('_');
var element_id = temp[1];

var price = $('#li_273').data("pricevalue"); 

var ordered = $(this).val();

var price_value = price * ordered;

price_value = parseFloat(price_value);
if(isNaN(price_value)){
    price_value = 0;
}

$("#li_273").data("pricevalue",price_value);
calculate_total_payment();  

});

Except I get the following error:
Uncaught TypeError: Cannot call method ‘data’ of null

It appears as tho my attempt to get the price value out of getElementById isn’t correct. Any suggestions?

UPDATE: The code above has been edited from your suggestions and thanks to all. It appears to be working just fine now.

Answer 1

This part is wrong:

var price = document.getElementById('#li_273').data("pricevalue").val();

Instead, you should use jQuery all the way here:

var price = $('#li_273').data("pricevalue"); 

Btw, you shouldn’t use .val() because .data() already returns a string. .val() is used exclusively for input elements such as <input> and <select> to name a few.

Update

Also, the rest of your code should be something like this:

var price_value = parseFloat(price);
if(isNaN(price_value)){
    price_value = 0;
}