Page Comparison

Example of synchronous

 code

{code:language=javascript|linenumbers=true|theme=DJango}// Make the API call 
var shippingEstimates = estimateShipping();

// Consume the result 
for (var = i; i < shippingEstimates.length; i++) {
    // Do something with the estimate

}
{code}

Example of asynchronous code

// Define a callback function 
function myCallbackFunction(shippingEstimates){
    for (var = i; i < shippingEstimates.length; i++) {
        // Do something with the estimate
    }
}

// Make the asynchronous call 
estimateShipping({'async': true, 'onComplete': myCallbackFunction});

Our recommendation is to make the the shipping estimate call asynchronous due to the time it can take calculate estimates.  Make sure that you give the customer a visual indication that shipping estimates are being calculated.  We do not recommend making calls that manipulate the cart asynchronous as it could cause inconsistancies in the global cart variables contents.
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