WMLScript » Operators » isvalid
- Syntax:
- isvalid
The
isvalid operator is used to test the validity of a variable or
the result type of executing an expression. A boolean value is returned
to denote the results of the test. A true is returned if the
variable or result type is valid. A false is returned if the
variable or result type is invalid.
Do not
confuse this operator with the URL.isValid function which is
used to validate the syntax of a URL address string.
The classic case of an invalid result type for an
expression is dividing by zero. In this example, as expected, the
isvalid operator returns a false.
Examples
Code:
<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC
"-//WAPFORUM//DTD WML 1.1//EN"
"http://www.WAPforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1">
<p>
isvalid
example
</p>
<do type="accept">
<go
href="IsvalidExample.wmls#findisvalid()" />
</do>
</card>
<card id="card2">
<p>
isvalid = $(valid)
</p>
</card>
</wml>Explanation:
Code for IsvalidExample.wml.
Language(s): WML
Code:
extern function findisvalid()
{
var zerodiv = 1/0;
var valid = isvalid(zerodiv);
WMLBrowser.setVar("valid", valid);
WMLBrowser.go("IsvalidExample.wml#card2");
};
Explanation:
Code for IsvalidExample.wmls.
Language(s): WML
See Also:
