Hidden Variables

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With hidden variables, you can reference variables while hiding the actual variable value in your HTML source. To use hidden variables:

  1. Define a variable for each string you want to hide.
  2. In the HTML block where the variables are referenced, use double dollar signs instead of a single dollar sign to reference the variables. For example, $$(X) instead of $(X).

Do not reference hidden variables with dynamically constructed variable names.

Example 1: Hidden variables in a HTML form

%HTML(INPUT) {
<form ...>
<p>Select fields to view:
<select name="field">
<option value="$$(name)"> Name
<option value="$$(addr)"> Address
.
.
.
</form>
%}
 
%DEFINE{
name="customer.name"
addr="customer.address"
%}
 
%FUNCTION(DTW_SQL) mySelect() {
  SELECT $(Field) FROM customer
%}
.
.
.

When the HTML form is displayed on a Web browser, $$(name) and $$(addr)are replaced with $(name) and $(addr) respectively, so the actual table and column names never appear on the HTML form. When the customer submits the form, the HTML(REPORT) block is called. When @mySelect() calls the FUNCTION block, $(Field) is substituted in the SQL statement with customer.name or customer.addr in the SQL query.


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