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<head>

<title>A javascript molecular weight calculator</title>

atom=new Array();

atom["H"]= 1.00794;

atom["He"]= 4.0026;

atom["Li"]= 6.941;

atom["Be"]= 9.01218;

atom["B"]= 10.811;

atom["C"]= 12.011;

atom["N"]= 14.0067;

atom["O"]= 15.9994;

atom["F"]= 18.9984;

atom["Ne"]= 20.1797;

atom["Na"]= 22.98977;

atom["Mg"]= 24.305;

atom["Al"]=26.98154;

atom["Si"]= 28.0855;

atom["P"]= 30.97376;

atom["S"]= 32.066;

atom["Cl"]= 35.4527;

atom["Ar"]= 39.948;

atom["K"]= 39.0983;

atom["Ca"]= 40.078;

atom["Sc"]= 44.9559;

atom["Ti"]= 47.88;

atom["V"]= 50.9415;

atom["Cr"]= 51.996;

atom["Mn"]= 54.938;

atom["Fe"]= 55.847;

atom["Co"]= 58.9332;

atom["Ni"]= 58.6934;

atom["Cu"]= 63.546;

atom["Zn"]= 65.39;

atom["Ga"]= 69.723;

atom["Ge"]= 72.61;

atom["As"]= 74.9216;

atom["Se"]= 78.96;

atom["Br"]= 79.904;

atom["Kr"]= 83.8;

atom["Rb"]= 85.4678;

atom["Sr"]= 87.62;

atom["Y"]= 88.9059;

atom["Zr"]= 91.224;

atom["Nb"]= 92.9064;

atom["Mo"]= 95.94;

atom["Tc"]= 98;

atom["Ru"]= 101.07;

atom["Rh"]= 102.9055;

atom["Pd"]= 106.42;

atom["Ag"]= 107.868;

atom["Cd"]= 112.41;

atom["In"]= 114.82;

atom["Sn"]= 118.71;

atom["Sb"]= 121.757;

atom["Te"]= 127.6;

atom["I"]= 126.9045;

atom["Xe"]= 131.29;

atom["Cs"]= 132.9054;

atom["Ba"]= 137.33;

atom["La"]= 138.9055;

atom["Hf"]= 178.49;

atom["Ta"]= 180.9479;

atom["W"]= 183.85;

atom["Re"]= 186.207;

atom["Os"]= 190.2;

atom["Ir"]= 192.22;

atom["Pt"]= 195.08;

atom["Au"]= 196.9665;

atom["Hg"]= 200.59;

atom["Tl"]= 204.383;

atom["Pb"]= 207.2;

atom["Bi"]= 208.9804;

atom["Po"]= 209;

atom["At"]= 210;

atom["Rn"]= 222;

atom["Fr"]= 223;

atom["Ra"]= 226.0254;

atom["Ac"]= 227;

atom["Rf"]= 261;

atom["Db"]= 262;

atom["Sg"]= 263;

atom["Bh"]= 262;

atom["Hs"]= 265;

atom["Mt"]= 266;

atom["Uun"]= 269;

atom["Uuu"]= 272;

atom["Uub"]= 277;

atom["Ce"]= 140.12;

atom["Pr"]= 140.9077;

atom["Nd"]= 144.24;

atom["Pm"]= 145;

atom["Sm"]= 150.36;

atom["Eu"]= 151.965;

atom["Gd"]= 157.25;

atom["Tb"]= 158.9253;

atom["Dy"]= 162.5;

atom["Ho"]= 164.9303;

atom["Er"]= 167.26;

atom["Tm"]= 168.9342;

atom["Yb"]= 173.04;

atom["Lu"]= 174.967;

atom["Th"]= 232.0381;

atom["Pa"]= 231.0359;

atom["U"]= 238.029;

atom["Np"]= 237.0482;

atom["Pu"]= 244;

atom["Am"]= 243;

atom["Cm"]= 247;

atom["Bk"]= 247;

atom["Cf"]= 251;

atom["Es"]= 252;

atom["Fm"]= 257;

atom["Md"]= 258;

atom["No"]= 259;

atom["Lr"]= 262;

uppercase="ABCDEFGHIJKLMNOPQRSTUVWXYZ";

lowercase="abcdefghijklmnopqrstuvwxyz";

number="0123456789";

function calculate(formula) {

total=new Array(); level=0; total[0]=0; i=0; mass=0; name=''; percision=8;

elmass=new Array();

for (i=0; i<elmass.length;i++) {

elmass[i]=null;

}

elmass[0]=new Array();

for (i=0; i<elmass[0].length;i++) {

elmass[0][i]=0;

}

i=0;

while (formula.charAt(i)!="") {

if ((uppercase+lowercase+number+"()").indexOf(formula.charAt(i))==-1)

i++;

while (formula.charAt(i)=="(") {

level++;

i++;

total[level]=0;

elmass[level]=new Array();

for (h=0; i<elmass[level].length;h++) {

elmass[level][i]=0;

}

if (formula.charAt(i)==")") {

mass=total[level];

name='';

level--;

}

else if (uppercase.indexOf(formula.charAt(i))!=-1) {

name=formula.charAt(i);

while (lowercase.indexOf(formula.charAt(i+1))!=-1 && formula.charAt(i+1)!="")

name+=formula.charAt(++i);

mass=atom[name];

massStr=mass+"";

if (massStr.indexOf(".")!=-1)

masspercis=(massStr.substring(massStr.indexOf(".")+1,massStr.length)).length;

else

masspercis=0;

percision=(percision==8 || percision>masspercis)?masspercis:percision;

}

var amount="";

while (number.indexOf(formula.charAt(i+1))!=-1 && formula.charAt(i+1)!="")

amount+=formula.charAt(++i);

if (amount=="") amount="1";

total[level]+=mass*parseInt(amount);

if (name=="") {

for (ele in elmass[level+1]) {

totalnumber=parseInt(elmass[level+1][ele])*amount

if (elmass[level][ele]==null)

elmass[level][ele]=totalnumber;

else

elmass[level][ele]=totalnumber+parseInt(elmass[level][ele]);

}

else {

if (elmass[level][name]==null)

elmass[level][name]=amount;

else

elmass[level][name]=parseInt(elmass[level][name])+parseInt(amount);

}

i++;

}

weight=rounded(total[0],percision);

previous=document.forms[1].elements[0].value;

document.forms[1].elements[0].value=document.forms[0].elements[0].value+":"+newline();

for (ele in elmass[0]) {

eltotal=eval(elmass[0][ele]*atom[ele]);

document.forms[1].elements[0].value+=elmass[0][ele]+" "+ele+" * "+atom[ele]+" = "+eltotal+" ("+rounded(eltotal/total[0]*100,percision)+"% of mass)"+newline();

}

document.forms[1].elements[0].value+= "Total:"+weight+" g/mol"+newline();

document.forms[1].elements[0].value+="------------------------------------------------------------"+newline()+previous;

document.forms[0].elements[0].value='';

document.forms[0].elements[0].focus();

}

function newline()

{

return (navigator.appName.substring(0,9)=="Microsoft")?'\r':'\n';

}

function rounded(number,percision)

{

return Math.round(number*Math.pow(10,percision))/Math.pow(10,percision);

}

</script>

</head>

<p><center><font size=+2>Atomic Mass Calculator</font></P></center>

Enter the molecular formula e.g. Cu(CH2H3O2)2H2O and hit Calculate,<BR> and it will find the total weight and the proportions of each element.

</form>

<form>

</body>

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