9. WMLScript Variables Vs WML Variables

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Note that WMLScript variables and WML variables are not the same thing. WMLScript variables are those you see in the last few sections. They are declared using the var keyword and they can only be used inside WMLScript functions.

WML variables are those variables whose values can be set and read using the WML markup language alone. For example, we can use the WML tag <setvar> to set the value of a WML variable without involving WMLScript. Further details about WML variables can be found in the "WML Variables" section of our WML tutorial.

WMLScript provides two functions in its WMLBrowser standard library for mobile Internet application developers to manipulate WML variables. They are setVar() and getVar().

9.1. Using WMLScript to Set the Value of a WML Variable

WMLScript's setVar() function is used to set the value of a WML variable. It should be used in the following form:

WMLBrowser.setVar(variable_name, value);

variable_name is the name of the WML variable you want to assign a value to, and value is the value you want to assign to variable_name. WMLScript requires value to be legal XML CDATA.

The setVar() function returns:

• true if the function call succeeds

• false if value cannot be assigned to variable_name

• invalid if variable_name or value is of the wrong syntax, e.g. variable_name contains forbidden characters (see "Setting Variable Values in WML" of our WML tutorial to learn what characters are allowed in WML variable names)

Here is an example demonstrating how to use the setVar() function:

WMLBrowser.setVar("message", "Hello World. Welcome to our WMLScript tutorial.");

The above line of script assigns the value "Hello World. Welcome to our WMLScript tutorial." to the WML variable message.

9.2. Using WMLScript to Obtain the Value of a WML Variable

WMLScript's getVar() function helps you obtain the value of a WML variable. It is used in the following form:

WMLBrowser.getVar(variable_name);

variable_name is the name of a WML variable.

The getVar() function returns:

• a string containing the value stored in the WML variable variable_name if the function call succeeds

• an empty string if the WML variable variable_name does not exist

• invalid if variable_name is of the wrong syntax, e.g. variable_name contains characters that are not allowed to appear in WML variable names.

Here is an example demonstrating how to use the getVar() function:

var wmlscript_variable = WMLBrowser.getVar("message");

When the WMLScript interpreter encounters the above line of script, the value of the WML variable message is assigned to the WMLScript variable wmlscript_variable.

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