Código:
if (this.form.HF_Multiplicador<%=i%>.value==1) this.form.TCat3.value = this.form.TCat3.value - this.form.HF_Bruto<%=i%>.value; if (this.form.HF_Multiplicador<%=i%>.value==3) this.form.TCat2.value = this.form.TCat2.value - this.form.HF_Bruto<%=i%>.value; if (this.form.HF_Multiplicador<%=i%>.value==50) OR (this.form.HF_Multiplicador<%=i%>.value==20) this.form.TCat1.value = this.form.TCat1.value - this.form.HF_Bruto<%=i%>.value;