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In-Depth Information
alert("Without conversion Sum = " + sum1 + "\r\n" +
"With conversion Sum = " + sum2);
});
As you can see, two numbers are stored in
localStorage
with the keys
number1
and
number2
,
respectively. Notice that this time, instead of using
setItem()
and
getItem()
, the code uses a familiar
dictionary-access syntax to store the items. The
sum1
variable stores the sum of the values of these two keys
without performing any conversion, whereas
sum2
stores their sum by first converting them to numbers
using the
Number()
function. An alert box displays the values of
sum1
and
sum2
, as shown in Figure 7-2.
Figure 7-2.
Adding numeric values after conversion
Figure 7-2 confirms that
localStorage
stores data in plain-text format and you need to convert it to an
appropriate data format before using it in further processing.
Storing date values is similar to storing numbers in that you need to convert date strings into
JavaScript
Date
objects. Listing 7-3 shows how this can be done.
Listing 7-3.
Storing Dates in
localStorage
$(document).ready(function () {
var storage = window.localStorage;
storage["date"] = new Date(2012,5,15);
var date1 = storage["date"];
try{
alert("Without conversion Year = " + date1.getFullYear());
}
catch(e){
alert("Data is not of date type!");
}
var date2 = new Date(storage["date"]));
try {
alert("With conversion Year = " + date2.getFullYear());
}
catch (e) {
