Handling User Input: Example
 
 
- Creating a TixControl widget that accepts % value:
 
tixControl .c -variable pcnt -value 100% \
    -validatecmd Validate -command Cmd 
proc Validate {v} {
    regsub {%} $v ““ v
    if [catch {set v [expr int($v)]%}] {
        set v 100%
    }
    return $v
}
proc Cmd {v} {puts “you have selected $v”}