function setCurrentRoom(){

   viewBox = SVGRoot.getAttribute('viewBox');
   var viewVals = viewBox.split(' ');
   currentPosition = parseFloat(viewVals[0]);

   if (currentPosition % 400 != 0) {
      currentRoomId = null;
      currentRoomLabel = "None.  Please scroll to desired room.";
   } else if (currentPosition / 400 == 0) {
      currentRoomId = "Room102";
      currentRoomLabel = "Room 102";
   } else if (currentPosition / 400 == -1) {
      currentRoomId = "Room101";
      currentRoomLabel = "Room 101";
   } else if (currentPosition / 400 == 1) {
      currentRoomId = "Room103";
      currentRoomLabel = "Room 103";
   }
document.getElementById("currentRoom").innerHTML = currentRoomLabel;

}
//panDoc() 函数控制向左和向右滚动：
function panDoc(evt){

//   currentPosition = parseFloat(viewVals[0]);
if (goLeft == true){
      if (currentPosition > -400) {
          currentPosition = currentPosition - 200;
      }
      goLeft = false;
   }

   if (goRight == true){
     if (currentPosition < 400) {
          currentPosition = currentPosition + 200;
     }
     goRight = false;
   }
viewBox = SVGRoot.getAttribute('viewBox');
   var viewVals = viewBox.split(' ');

   viewVals[0] = currentPosition;
   SVGRoot.setAttribute('viewBox', viewVals.join(' '));

setCurrentRoom();
} // end function panDoc()

function toExec(){

   if (currentRoomId == null) {

      alert("Ambiguous room position! \n Please align a room "+
         "precisely before attempting to change room type.");

   } else {

      SVGDoc.getElementById(currentRoomId+"Rect")
                                      .setAttribute("fill", "#FF0000");

      innerSVG = SVGDoc.getElementById(currentRoomId);

      oldChild = SVGDoc.getElementById(currentRoomId+"Label");
      innerSVG.removeChild(oldChild);

      oldChild = SVGDoc.getElementById(currentRoomId+"Type");
      innerSVG.removeChild(oldChild);
myData = SVGDoc.createTextNode("Executive Office");
      newText = SVGDoc.createElementNS(svgns, "text");
      newText.setAttributeNS(null, "id", currentRoomId+"Type");
      newText.setAttributeNS(null, "x", "55px");
      newText.setAttributeNS(null, "y", "100px");
      newText.setAttributeNS(null, "font-size", "24pt");
      newText.setAttributeNS(null, "stroke", "white");
      newText.appendChild(myData);
      SVGDoc.getElementById(currentRoomId).appendChild(newText);

      myData = SVGDoc.createTextNode(currentRoomLabel);
      newText = SVGDoc.createElementNS(svgns, "text");
      newText.setAttributeNS(null, "id", currentRoomId+"Label");
      newText.setAttributeNS(null, "x", "55px");
      newText.setAttributeNS(null, "y", "150px");
      newText.setAttributeNS(null, "font-size", "24pt");
      newText.setAttributeNS(null, "stroke", "white");
      newText.appendChild(myData);
      SVGDoc.getElementById(currentRoomId).appendChild(newText);

   }

} // end function toExec()
试试这几个函数，我用得可以