function calcul_surface(){
	with (document.surface){
		switch(unite1.value)
		{
			case 'km':
				switch(unite2.value)
				{
					case 'km' : resultat.value = roundit(data.value); break;
					case 'm' : resultat.value =  roundit(data.value*1000000);break;
					case 'dm' : resultat.value =  roundit(data.value*100000000);break;
					case 'cm' : resultat.value =  roundit(data.value*10000000000);break;
					case 'ha' : resultat.value =  roundit(data.value*100);break;
					case 'a' : resultat.value =  roundit(data.value*10000);break;
					case 'da' : resultat.value =  roundit(data.value*100000);break;
					case 'ca' : resultat.value =  roundit(data.value*1000000);break;
					case 'mi' : resultat.value =  roundit(data.value*0.3861);break;
					case 'yd' : resultat.value =  roundit(data.value*1195985);break;
					case 'ft' : resultat.value =  roundit(data.value*10763870);break;
					case 'inc' : resultat.value =  roundit(data.value*1549997000);break;
					case 'fe' : resultat.value =  roundit(data.value*(1000000/4200));break;
					case 'qa' : resultat.value =  roundit(data.value*(1000000/12.6));break;
					case 'aus' : resultat.value =  roundit(data.value*247.1044);break;
					case 'ai' : resultat.value =  roundit(data.value*247.11);break;
				}
			break;
			case 'm':
				switch(unite2.value)
				{
					case 'm' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/1000000);break;
					case 'dm' : resultat.value =  roundit(data.value*100);break;
					case 'cm' : resultat.value =  roundit(data.value*10000);break;
					case 'ha' : resultat.value =  roundit(data.value/10000);break;
					case 'a' : resultat.value =  roundit(data.value/100);break;
					case 'da' : resultat.value =  roundit(data.value/10);break;
					case 'ca' : resultat.value =  roundit(data.value);break;
					case 'mi' : resultat.value =  roundit(data.value*0.0000003861);break;
					case 'yd' : resultat.value =  roundit(data.value*1.195985);break;
					case 'ft' : resultat.value =  roundit(data.value*10.76387);break;
					case 'inc' : resultat.value =  roundit(data.value*1549.997);break;
					case 'fe' : resultat.value =  roundit(data.value/4200);break;
					case 'qa' : resultat.value =  roundit(data.value/12.6);break;
					case 'aus' : resultat.value =  roundit(data.value*0.0002471044);break;
					case 'ai' : resultat.value =  roundit(data.value*0.00024711);break;
				}
			break;
			case 'dm':
				switch(unite2.value)
				{
					case 'dm' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/100000000);break;
					case 'm' : resultat.value =  roundit(data.value/100);break;
					case 'cm' : resultat.value =  roundit(data.value*100);break;
					case 'ha' : resultat.value =  roundit(data.value/1000000);break;
					case 'a' : resultat.value =  roundit(data.value/10000);break;
					case 'da' : resultat.value =  roundit(data.value/1000);break;
					case 'ca' : resultat.value =  roundit(data.value/100);break;
					case 'mi' : resultat.value =  roundit(data.value*0.000000003861);break;
					case 'yd' : resultat.value =  roundit(data.value*0.01195985);break;
					case 'ft' : resultat.value =  roundit(data.value*0.1076387);break;
					case 'inc' : resultat.value =  roundit(data.value*15.49997);break;
					case 'fe' : resultat.value =  roundit(data.value/420000);break;
					case 'qa' : resultat.value =  roundit(data.value/0.126);break;
					case 'aus' : resultat.value =  roundit(data.value*0.000002471044);break;
					case 'ai' : resultat.value =  roundit(data.value*0.0000024711);break;
				}
			break;
			case 'cm':
				switch(unite2.value)
				{
					case 'cm' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/10000000000);break;
					case 'm' :resultat.value =  roundit(data.value/10000);break;
					case 'dm' : resultat.value =  roundit(data.value/100);break;
					case 'ha' : resultat.value =  roundit(data.value/100000000);break;
					case 'a' : resultat.value =  roundit(data.value/1000000);break;
					case 'da' : resultat.value =  roundit(data.value/100000);break;
					case 'ca' : resultat.value =  roundit(data.value/10000);break;
					case 'mi' : resultat.value =  roundit(data.value*0.00000000003861);break;
					case 'yd' : resultat.value =  roundit(data.value*0.0001195985);break;
					case 'ft' : resultat.value =  roundit(data.value*0.001076387);break;
					case 'inc' : resultat.value =  roundit(data.value*0.1549997);break;
					case 'fe' : resultat.value =  roundit(data.value/42000000);break;
					case 'qa' : resultat.value =  roundit(data.value/0.00126);break;
					case 'aus' : resultat.value =  roundit(data.value*0.00000002471044);break;
					case 'ai' : resultat.value =  roundit(data.value*0.000000024711);break;
				}
			break;
			case 'ha':
				switch(unite2.value)
				{
					case 'ha' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/100);break;
					case 'm' : resultat.value =  roundit(data.value*10000);break;
					case 'dm' : resultat.value =  roundit(data.value*10000000);break;
					case 'cm' : resultat.value =  roundit(data.value*1000000000);break;
					case 'a' : resultat.value =  roundit(data.value*100);break;
					case 'da' : resultat.value =  roundit(data.value*1000);break;
					case 'ca' : resultat.value =  roundit(data.value*10000);break;
					case 'mi' : resultat.value =  roundit(data.value*38.61);break;
					case 'yd' : resultat.value =  roundit(data.value*11959.85);break;
					case 'ft' : resultat.value =  roundit(data.value*107638.7);break;
					case 'inc' : resultat.value =  roundit(data.value*15499970);break;
					case 'fe' : resultat.value =  roundit(data.value*(100/42));break;
					case 'qa' : resultat.value =  roundit(data.value*(10000/12.6));break;
					case 'aus' : resultat.value =  roundit(data.value*2.471044);break;
					case 'ai' : resultat.value =  roundit(data.value*2.4711);break;
				}
			break;
			case 'a':
				switch(unite2.value)
				{
					case 'a' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/10000);break;
					case 'm' : resultat.value =  roundit(data.value*100);break;
					case 'dm' : resultat.value =  roundit(data.value*100000);break;
					case 'cm' : resultat.value =  roundit(data.value*10000000);break;
					case 'ha' : resultat.value =  roundit(data.value/100);break;
					case 'da' : resultat.value =  roundit(data.value*10);break;
					case 'ca' : resultat.value =  roundit(data.value*100);break;
					case 'mi' : resultat.value =  roundit(data.value*0.3861);break;
					case 'yd' : resultat.value =  roundit(data.value*119.5985);break;
					case 'ft' : resultat.value =  roundit(data.value*1076.387);break;
					case 'inc' : resultat.value =  roundit(data.value*154999.7);break;
					case 'fe' : resultat.value =  roundit(data.value/42);break;
					case 'qa' : resultat.value =  roundit(data.value*(100/12.6));break;
					case 'aus' : resultat.value =  roundit(data.value*0.02471044);break;
					case 'ai' : resultat.value =  roundit(data.value*0.024711);break;
				}
			break;
			case 'da':
				switch(unite2.value)
				{
					case 'da' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/100000);break;
					case 'm' : resultat.value =  roundit(data.value*10);break;
					case 'dm' : resultat.value =  roundit(data.value*10000);break;
					case 'cm' : resultat.value =  roundit(data.value*1000000);break;
					case 'ha' : resultat.value =  roundit(data.value/1000);break;
					case 'a' : resultat.value =  roundit(data.value/10);break;
					case 'ca' : resultat.value =  roundit(data.value*10);break;
					case 'mi' : resultat.value =  roundit(data.value*0.03861);break;
					case 'yd' : resultat.value =  roundit(data.value*11.95985);break;
					case 'ft' : resultat.value =  roundit(data.value*107.6387);break;
					case 'inc' : resultat.value =  roundit(data.value*15499.97);break;
					case 'fe' : resultat.value =  roundit(data.value/420);break;
					case 'qa' : resultat.value =  roundit(data.value*(10/12.6));break;
					case 'aus' : resultat.value =  roundit(data.value*0.002471044);break;
					case 'ai' : resultat.value =  roundit(data.value*0.0024711);break;
				}
			break;
			case 'ca':
				switch(unite2.value)
				{
					case 'ca' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value/1000000);break;
					case 'm' : resultat.value =  roundit(data.value);break;
					case 'dm' : resultat.value =  roundit(data.value*1000);break;
					case 'cm' : resultat.value =  roundit(data.value*100000);break;
					case 'ha' : resultat.value =  roundit(data.value/10000);break;
					case 'a' : resultat.value =  roundit(data.value/100);break;
					case 'da' : resultat.value =  roundit(data.value/10);break;
					case 'mi' : resultat.value =  roundit(data.value*0.003861);break;
					case 'yd' : resultat.value =  roundit(data.value*1.195985);break;
					case 'ft' : resultat.value =  roundit(data.value*10.76387);break;
					case 'inc' : resultat.value =  roundit(data.value*1549.997);break;
					case 'fe' : resultat.value =  roundit(data.value/4200);break;
					case 'qa' : resultat.value =  roundit(data.value/12.6);break;
					case 'aus' : resultat.value =  roundit(data.value*0.0002471044);break;
					case 'ai' : resultat.value =  roundit(data.value*0.00024711);break;
				}
			break;
			case 'mi':
				switch(unite2.value)
				{
					case 'mi' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*2.589979);break;
					case 'm' : resultat.value =  roundit(data.value*2589979);break;
					case 'dm' : resultat.value =  roundit(data.value*258997900);break;
					case 'cm' : resultat.value =  roundit(data.value*25899790000);break;
					case 'ha' : resultat.value =  roundit(data.value*258.9979);break;
					case 'a' : resultat.value =  roundit(data.value*25899.79);break;
					case 'da' : resultat.value =  roundit(data.value*258997.9);break;
					case 'ca' : resultat.value =  roundit(data.value*2589979);break;
					case 'yd' : resultat.value =  roundit(data.value*3097576.034315);break;
					case 'ft' : resultat.value =  roundit(data.value*27878197.25873);break;
					case 'inc' : resultat.value =  roundit(data.value*4014459680.063);break;
					case 'fe' : resultat.value =  roundit(data.value*616.66166666667);break;
					case 'qa' : resultat.value =  roundit(data.value*205553.88888889);break;
					case 'aus' : resultat.value =  roundit(data.value*6.399952076);break;
					case 'ai' : resultat.value =  roundit(data.value*6.40009711);break;
				}
			break;
			case 'aus':
				switch(unite2.value)
				{
					case 'aus' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.004046873);break;
					case 'm' : resultat.value =  roundit(data.value*4046.873);break;
					case 'dm' : resultat.value =  roundit(data.value*404687.3);break;
					case 'cm' : resultat.value =  roundit(data.value*40468730);break;
					case 'ha' : resultat.value =  roundit(data.value*0.4046873);break;
					case 'a' : resultat.value =  roundit(data.value*40.46873);break;
					case 'da' : resultat.value =  roundit(data.value*404.6873);break;
					case 'ca' : resultat.value =  roundit(data.value*4046.873);break;
					case 'mi' : resultat.value =  roundit(data.value*15.624976653);break;
					case 'yd' : resultat.value =  roundit(data.value*4839.999404905);break;
					case 'ft' : resultat.value =  roundit(data.value*43560.01487851);break;
					case 'inc' : resultat.value =  roundit(data.value*6272641.009381);break;
					case 'fe' : resultat.value =  roundit(data.value*0.963541190476);break;
					case 'qa' : resultat.value =  roundit(data.value*3211.803968254);break;
					case 'ai' : resultat.value =  roundit(data.value*1.00002278703);break;
				}
			break;
			case 'ai':
				switch(unite2.value)
				{
					case 'ai' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.004046842);break;
					case 'm' : resultat.value =  roundit(data.value*4046.842);break;
					case 'dm' : resultat.value =  roundit(data.value*404684.2);break;
					case 'cm' : resultat.value =  roundit(data.value*40468420);break;
					case 'ha' : resultat.value =  roundit(data.value*0.4046842);break;
					case 'a' : resultat.value =  roundit(data.value*40.46842);break;
					case 'da' : resultat.value =  roundit(data.value*404.6842);break;
					case 'ca' : resultat.value =  roundit(data.value*4046.842);break;
					case 'mi' : resultat.value =  roundit(data.value*15,624856962);break;
					case 'yd' : resultat.value =  roundit(data.value*4839.96232937);break;
					case 'ft' : resultat.value =  roundit(data.value*43559.68119854);break;
					case 'inc' : resultat.value =  roundit(data.value*6272592.959474);break;
					case 'fe' : resultat.value =  roundit(data.value*0.963533809524);break;
					case 'qa' : resultat.value =  roundit(data.value*3211.7793650794);break;
					case 'aus' : resultat.value =  roundit(data.value*0.999992464305);break;
				}
			break;
			case 'yd':
				switch(unite2.value)
				{
					case 'yd' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.0000008361307);break;
					case 'm' : resultat.value =  roundit(data.value*0.8361307);break;
					case 'dm' : resultat.value =  roundit(data.value*83.61307);break;
					case 'cm' : resultat.value =  roundit(data.value*8361.307);break;
					case 'ha' : resultat.value =  roundit(data.value*0.00008361307);break;
					case 'a' : resultat.value =  roundit(data.value*0.008361307);break;
					case 'da' : resultat.value =  roundit(data.value*0.08361307);break;
					case 'ca' : resultat.value =  roundit(data.value*0.8361307);break;
					case 'mi' : resultat.value =  roundit(data.value*0.00000032283);break;
					case 'ft' : resultat.value =  roundit(data.value*9.000002157809);break;
					case 'inc' : resultat.value =  roundit(data.value*1296.0000766079);break;
					case 'fe' : resultat.value =  roundit(data.value*0.000199078738);break;
					case 'qa' : resultat.value =  roundit(data.value*10.53524682);break;
					case 'aus' : resultat.value =  roundit(data.value*0.000206611575);break;
					case 'ai' : resultat.value =  roundit(data.value*0.000206616257);break;
				}
			break;
			case 'ft':
				switch(unite2.value)
				{
					case 'ft' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.00000009290341);break;
					case 'm' : resultat.value =  roundit(data.value*0.09290341);break;
					case 'dm' : resultat.value =  roundit(data.value*9.290341);break;
					case 'cm' : resultat.value =  roundit(data.value*929.0341);break;
					case 'ha' : resultat.value =  roundit(data.value*0.000009290341);break;
					case 'a' : resultat.value =  roundit(data.value*0.0009290341);break;
					case 'da' : resultat.value =  roundit(data.value*0.009290341);break;
					case 'ca' : resultat.value =  roundit(data.value*0.09290341);break;
					case 'mi' : resultat.value =  roundit(data.value*0.00000003587);break;
					case 'yd' : resultat.value =  roundit(data.value*0.111111084809);break;
					case 'inc' : resultat.value =  roundit(data.value*144.00000678977);break;
					case 'fe' : resultat.value =  roundit(data.value*0.00002211986);break;
					case 'qa' : resultat.value =  roundit(data.value*1.170582966);break;
					case 'aus' : resultat.value =  roundit(data.value*0.000022956841);break;
					case 'ai' : resultat.value =  roundit(data.value*0.000022957362);break;
				}
			break;
			case 'inc':
				switch(unite2.value)
				{
					case 'inc' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.0000000006451626);break;
					case 'm' : resultat.value =  roundit(data.value*0.0006451626);break;
					case 'dm' : resultat.value =  roundit(data.value*0.06451626);break;
					case 'cm' : resultat.value =  roundit(data.value*6.451626);break;
					case 'ha' : resultat.value =  roundit(data.value*0.00000006451626);break;
					case 'a' : resultat.value =  roundit(data.value*0.000006451626);break;
					case 'da' : resultat.value =  roundit(data.value*0.00006451626);break;
					case 'ca' : resultat.value =  roundit(data.value*0.0006451626);break;
					case 'mi' : resultat.value =  roundit(data.value*0.000000000249);break;
					case 'yd' : resultat.value =  roundit(data.value*0.000771604792);break;
					case 'ft' : resultat.value =  roundit(data.value*0.006944446355);break;
					case 'data' : resultat.value =  roundit(data.value*1.000000094512);break;
					case 'fe' : resultat.value =  roundit(data.value*0.00000015361);break;
					case 'qa' : resultat.value =  roundit(data.value*0.00812904876);break;
					case 'aus' : resultat.value =  roundit(data.value*0.000000159423);break;
					case 'ai' : resultat.value =  roundit(data.value*0.000000159426);break;
				}
			break;
			case 'fe':
				switch(unite2.value)
				{
					case 'fe' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.0042);break;
					case 'm' : resultat.value =  roundit(data.value*4200);break;
					case 'dm' : resultat.value =  roundit(data.value*420000);break;
					case 'cm' : resultat.value =  roundit(data.value*42000000);break;
					case 'ha' : resultat.value =  roundit(data.value*0.42);break;
					case 'a' : resultat.value =  roundit(data.value*42);break;
					case 'da' : resultat.value =  roundit(data.value*420);break;
					case 'ca' : resultat.value =  roundit(data.value*4200);break;
					case 'mi' : resultat.value =  roundit(data.value*0.00162162);break;
					case 'yd' : resultat.value =  roundit(data.value*5023.137);break;
					case 'ft' : resultat.value =  roundit(data.value*45208.254);break;
					case 'inc' : resultat.value =  roundit(data.value*6509987.4);break;
					case 'qa' : resultat.value =  roundit(data.value*(1000/3));break;
					case 'aus' : resultat.value =  roundit(data.value*1.03783848);break;
					case 'ai' : resultat.value =  roundit(data.value*1.037862);break;
				}
			break;
			case 'qa':
				switch(unite2.value)
				{
					case 'qa' : resultat.value = data.value; break;
					case 'km' : resultat.value =  roundit(data.value*0.0000126);break;
					case 'm' : resultat.value =  roundit(data.value*12.6);break;
					case 'dm' : resultat.value =  roundit(data.value*1260);break;
					case 'cm' : resultat.value =  roundit(data.value*126000);break;
					case 'ha' : resultat.value =  roundit(data.value*0.00126);break;
					case 'a' : resultat.value =  roundit(data.value*0.126);break;
					case 'da' : resultat.value =  roundit(data.value*1.26);break;
					case 'ca' : resultat.value =  roundit(data.value*12.6);break;
					case 'mi' : resultat.value =  roundit(data.value*0.00000486486);break;
					case 'yd' : resultat.value =  roundit(data.value*15.069411);break;
					case 'ft' : resultat.value =  roundit(data.value*135.624762);break;
					case 'inc' : resultat.value =  roundit(data.value*19529.9622);break;
					case 'fe' : resultat.value =  roundit(data.value*0.003);break;
					case 'aus' : resultat.value =  roundit(data.value*0.00311351544);break;
					case 'ai' : resultat.value =  roundit(data.value*0.003113586);break;
				}
			break;
				
		}
	}
}