Required library edition: 
 Required library file: dhtmlxtoolbar.js
adds a slider to webbar
 id - id of a slider
 
 pos - position of a slider
 
 len - length (width) of a slider (px)
 
 valueMin - minimal available value of a slider
 
 valueMax - maximal available value of a slider
 
 valueNow - initial current value of a slider
 
 textMin - label for minimal value side (on the left side)
 
 textMax - label for maximal value side (on the right side)
 
 tip - tooltip template (%v will replaced with current value)
 
    toolbar.addSlider(id, pos, len, valueMin, valueMax, valueNow, textMin, textMax, tip);