Using Dynamic Attributes
 
 Using dynamic attributes, you can set VDL and HTML attributes on elements using the result of VDL expressions.  
 
Expression Value
  The most common use case is inside a 
  vdl-repeat or 
  vdl-repeat-contents loop where the value or index of the loop iteration is needed to populate an attribute in a VDL or HTML element. 
  
 
<div vdl-repeat="=s,i in scenarios"
     vdl-attr="={id: 'scenarioId'+s.id}">
</div> The above example results in each 
  div in the repeat loop gaining an id attribute based on combining the string 
  scenarioId with the 
  id of each scenario referenced in the loop - i.e. all scenarios on the shelf. 
 String Value
  A slightly different syntax exists for those occasions when you can provide the value of 
  vdl-attr as a string. 
  
 
<vdl-row vdl-repeat-contents="=num, idx in ['a','b','c']">
    <vdl-column vdl-attr="size: idx+1">
        ...
    </vdl-column>
</vdl-row> This works in the same way but is slightly more concise. 
  
