// von -20 bis 30 °C
var pressure=new Array(
103,114,125,137,150,165,181,198,217,237,260,284,310,337,
368,401,437,476,517,562,611,657,705,759,813,872,935,1002,
1073,1148,1228,1312,1403,1498,1599,1706,1818,1937,2065,
2197,2340,2487,2645,2810,2985,3169,3362,3566,3781,4006,
4244);  


      function get_value() {
         var v1=parseFloat(document.getElementById("val1").value.replace(",","."));
         var result="fehlerhafte Eingabe";

         if ((v1>=-20) && (v1<=30)) {
          var tint=parseInt(v1+20);
          var tfloat=parseFloat(v1+20);
          var delta=tfloat-tint;
          result="Dampfs&auml;ttigungsdruck bei "+v1+" °C: <b>"+parseInt(pressure[tint]+(pressure[tint+1]-pressure[tint])*delta)+" Pa</b>";
          }

         document.getElementById("result").innerHTML=result;
      }