http://www.aps.anl.gov/APS_Engineering_Support_Division/Mechanical_Operations_and_Maintenance/Calculators/ElasticBeam2.html


HTML COLORS CODE tbv CSS:
http://html-color-codes.info/


afronden van getallen:
http://www.javascriptkit.com/javatutors/round.shtml






http://www.javascriptkit.com/javatutors/combos1.shtml

http://www.javascriptkit.com/javatutors/combos2.shtml


http://www.javascriptkit.com/script/script2/combodescrip1.shtml