Stringing Things Along - Slice And Dice (
Page 4 of 7 )
Next up,
the substring() method. As the name implies, this is the function that allows
you to slice and dice strings into smaller strings. Here's what it looks like:
String.substring(start, end)
where "start" is the
position to begin slicing at, and "end" is the position to end at (note that in
JavaScript, the first character of a string is at position 0).
Here's an
example which demonstrates how this works:
<script language="Javascript">
// set string
var str = "The horse munched pink flowers, waiting for the elephant to
make its presence felt.";
// returns "pink flowers"
alert(str.substring(18, 30));
</script>
You can use this function to split a
string into smaller chunks of a fixed size,
<script language="Javascript">
// set string
var str = "The horse munched pink flowers, waiting for the elephant to
make its presence felt.";
// chunk size
var size = 9;
// counter
var count = 0;
/* returns
The horse
munched
pink flow
ers, wait
ing for t
he elepha
nt to mak
e its pre
sence fel
t.
*/
while ((size*count) < str.length)
{
temp = str.substring(size*count, (size*count)+size);
count++;
document.write(temp + "\r\n");
}
</script>You can also use the substring()
method to extract a particular character from a string,
<script language="Javascript">
// set string
var str = "The horse munched pink flowers, waiting for the elephant to
make its presence felt.";
// returns "p"
alert(str.substring(18,19));
</script>/pre>
Similar, though not identical,
is the substr() method, which returns a substring, given the start position and
the number of characters to be extracted. This method differs from the
substring() method discussed above in that its second argument is not the end
position, but the number of characters to be returned - as illustrated
below:
<script language="Javascript">
// set string
var str = "Batman and Robin";
// returns "Batman"
alert(str.substr(0,6));
</script>
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