Hi everyone I adapted this little script to make a dynamic sum of values inserted in a list box. However I can only get it to work in firefox but not in explorer. Can anyone tell me why? thanx! [hr] //in the head of my document: <script type ="text/javascript"> <!-- Begin function startCalc(){ interval = setInterval("calc()",1); } function calc(){ one = document.form.comm.value; two = document.form.cost.value; three = document.form.hres.value; four = document.form.qual.value; five = document.form.scop.value; six = document.form.time.value; document.form.total.value = (one * one) + (two * two) + (three * three) + (four * four) + (five * five) + (six * six); } function stopCalc(){ clearInterval(interval); } // End --> </script> //in the body <select name='comm' size ='1' onFocus="startCalc();" onBlur="stopCalc();"> <option selected='selected'>0</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> <select name='cost' size ='1' onFocus="startCalc();" onBlur="stopCalc();"> <option selected='selected'>0</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> <select name='hres' size ='1' onFocus="startCalc();" onBlur="stopCalc();"> <option selected='selected'>0</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> <select name='qual' size ='1' onFocus="startCalc();" onBlur="stopCalc();"> <option selected='selected'>0</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> <select name='scop' size ='1' onFocus="startCalc();" onBlur="stopCalc();"> <option selected='selected'>0</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> <select name='time' size ='1' onFocus="startCalc();" onBlur="stopCalc();"> <option selected='selected'>0</option> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select>