Change link dynamically

changeLink.js

//situation: using SharePoint forms designer.  
//get value from field, store in variable and use that to search for a particular document control number
var dcn = fd.field('DocumentNumber').control()._el().text();
//var dcn2 = fd.field('DocumentControlNumber').control().value();



fd.field('DocumentNumber').control()._el().wrap('<a href="http://sharepoint.company.com/Pages/search.aspx?k='+dcn+'"></a>');