I dont think you need to use jQuery at all, just simple JavaScript...
Save the date as a string:
dte = fecha.value;//2014-01-06
Split the string to get the day, month & year values...
dteSplit = dte.split("-");
yr = dteSplit[0][2] + dteSplit[0][3]; //special yr format, take last 2 digits
month = dteSplit[1];
day = dteSplit[2];
Rejoin into final date string:
finalDate = month+"-"+day+"-"+year