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function calc(){showquickmsg("calculating...",true);observedvalue=trimAll(gObj("observedvalue").value);truevalue=trimAll(gObj("truevalue").value);if(!isNumber(observedvalue)){showquickmsg("observed value need to be numeric",true);return }else{if(!isNumber(truevalue)){showquickmsg("true value need to be numeric",true);return }}observedvalue=parseFloat(observedvalue);truevalue=parseFloat(truevalue);percentError=100*(observedvalue-truevalue)/truevalue;outPutStr="Percent error: <font color=green><b>"+percentError.toPrecision(4)+"%</b></font>";showquickmsg(outPutStr,false)};