cart js adding to cart tutorial code example

Example: code to add to cart by javascript

// Appends the required hidden values to PayPal's form before submitting

populatePayPalForm: function() {
    var self = this;
    if( self.$paypalForm.length ) {
        var $form = self.$paypalForm;
        var cart = self._toJSONObject( self.storage.getItem( self.cartName ) );
        var shipping = self.storage.getItem( self.shippingRates );
        var numShipping = self._convertString( shipping );
        var cartItems = cart.items;
        var singShipping = Math.floor( numShipping / cartItems.length );

        $form.attr( "action", self.paypalURL );
        $form.find( "input[name='business']" ).val( self.paypalBusinessEmail );
        $form.find( "input[name='currency_code']" ).val( self.paypalCurrency );

        for( var i = 0; i < cartItems.length; ++i ) {
            var cartItem = cartItems[i];
            var n = i + 1;
            var name = cartItem.product;
            var price = cartItem.price;
            var qty = cartItem.qty;

            $( "<div/>" ).html( "<input type='hidden' name='quantity_" + n + "' value='" + qty + "'/>" ).
            insertBefore( "#paypal-btn" );
            $( "<div/>" ).html( "<input type='hidden' name='item_name_" + n + "' value='" + name + "'/>" ).
            insertBefore( "#paypal-btn" );
            $( "<div/>" ).html( "<input type='hidden' name='item_number_" + n + "' value='SKU " + name + "'/>" ).
            insertBefore( "#paypal-btn" );
            $( "<div/>" ).html( "<input type='hidden' name='amount_" + n + "' value='" + self._formatNumber( price, 2 ) + "'/>" ).
            insertBefore( "#paypal-btn" );
            $( "<div/>" ).html( "<input type='hidden' name='shipping_" + n + "' value='" + self._formatNumber( singShipping, 2 ) + "'/>" ).
            insertBefore( "#paypal-btn" );

        }

    }
}