等高手来回答吧！

function new_text(id,text,classid,pevent){
 var tdata = svgdoc.createTextNode(text);
 var newobj = svgdoc.createElementNS(svgns, "text");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"class",classid);
 newobj.getStyle.setProperty("pointer-events",pevent);
 newobj.appendChild(tdata);
 return newobj; 
}

function new_rect(id,x,y,rx,ry,wid,hei,classid){
 var newobj=svgdoc.createElementNS(svgns,"rect");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"x",x);
 newobj.setAttributeNS(null,"y",y);
 newobj.setAttributeNS(null,"rx",rx);
 newobj.setAttributeNS(null,"ry",ry);
 newobj.setAttributeNS(null,"width",wid);
 newobj.setAttributeNS(null,"height",hei);
 newobj.setAttributeNS(null,"class",classid);
 return newobj;
}

function new_line(id,x1,y1,x2,y2,classid){
 var newobj=svgdoc.createElementNS(svgns,"line");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"x1",x1);
 newobj.setAttributeNS(null,"y1",y1);
 newobj.setAttributeNS(null,"x2",x2);
 newobj.setAttributeNS(null,"y2",y2);
 newobj.setAttributeNS(null,"class",classid);
 return newobj;
}

/**
* Draw Line
* cDis - arc center offset
* pDis - start&end point offset
*/
function new_linepath(id,classname,cDis,pDis,x1,y1,x2,y2){
  var oline=svgdoc.createElementNS(svgns,"path");

  var dx=x2-x1;
  var dy=y2-y1;
  //alert(dx + "," + dy);
  var dt=0;
  if(dx==0 && dy==0 || dx==0 && dy>0){
   dt=0;
  }
  else if(dx==0 && dy<0){
   dt=pi;
  }
  else if(dy==0 && dx>0){
   dt=pi/2;
  }
  else if(dy==0 && dx<0){
   dt=pi*3/2;
  }
  else{
   dt=Math.atan(Math.abs(dy)/Math.abs(dx));
  }
  var cx=(x1+x2)/2;
  var cy=(y1+y2)/2;
  var x1,y1,x2,y2,scx,scy;
  if(dx>0 && dy>0){
   x1=x1-pDis*tscale*Math.sin(dt);
   y1=y1+pDis*tscale*Math.cos(dt);
   x2=x2-pDis*tscale*Math.sin(dt);
   y2=y2+pDis*tscale*Math.cos(dt);

   scx=cx-cDis*tscale*Math.sin(dt);
   scy=cy+cDis*tscale*Math.cos(dt);
  }
  if(dx>0 && dy<0){
   x1=x1+pDis*tscale*Math.sin(dt);
   y1=y1+pDis*tscale*Math.cos(dt);
   x2=x2+pDis*tscale*Math.sin(dt);
   y2=y2+pDis*tscale*Math.cos(dt);
   scx=cx+cDis*tscale*Math.sin(dt);
   scy=cy+cDis*tscale*Math.cos(dt);
   //alert(Math.sin(dt) + "," + Math.cos(dt));
   //alert(scx+","+scy);
  }
  if(dx<0 && dy<0){
   x1=x1+pDis*tscale*Math.sin(dt);
   y1=y1-pDis*tscale*Math.cos(dt);
   x2=x2+pDis*tscale*Math.sin(dt);
   y2=y2-pDis*tscale*Math.cos(dt);
   scx=cx+cDis*tscale*Math.sin(dt);
   scy=cy-cDis*tscale*Math.cos(dt);
   //alert(x1+","+y1+","+x2+","+y2);
  }
  if(dx<0 && dy>0){
   x1=x1-pDis*tscale*Math.sin(dt);
   y1=y1-pDis*tscale*Math.cos(dt);
   x2=x2-pDis*tscale*Math.sin(dt);
   y2=y2-pDis*tscale*Math.cos(dt);
   scx=cx-cDis*tscale*Math.sin(dt);
   scy=cy-cDis*tscale*Math.cos(dt);
   //alert(Math.sin(dt) + "," + Math.cos(dt));
   //alert(scx+","+scy);
  }

  y1=y1*(-1);
  y2=y2*(-1);
  scy=scy*(-1);
  
  var ssss="M"+x1+","+y1+" C"+scx+","+scy+" "+scx+","+scy+" "+x2+","+y2;
  oline.setAttributeNS(null,"d",ssss);
  oline.setAttributeNS(null,"id",id);
  oline.setAttributeNS(null,"class",classname);
 return oline;
}

function new_animate(id,attName,attValue,durTime,repeatCount){
 var newobj=svgdoc.createElementNS(svgns, "animate");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"attributeName",attName);
 newobj.setAttributeNS(null,"values",attValue);
 newobj.setAttributeNS(null,"dur",durTime);
 newobj.setAttributeNS(null,"repeatCount",repeatCount);
 return newobj;
}

function new_link(id,href){
 var newobj = svgdoc.createElementNS(svgns, id);
 newobj.setAttributeNS(xlinkns, "xlink:href", href);
 return newobj;
}

function new_use(id,x,y){
 var newobj=svgdoc.createElementNS(svgns,"use");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"x",x);
 newobj.setAttributeNS(null,"y",y);
 //newobj.setAttributeNS(null,"width",10);
 //newobj.setAttributeNS(null,"height",10);
 return newobj;
}

function new_image(id,x,y,wid,hei,href){
 var newobj=svgdoc.createElementNS(svgns,"image");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"x",x);
 newobj.setAttributeNS(null,"y",y);
 newobj.setAttributeNS(null,"width",wid);
 newobj.setAttributeNS(null,"height",hei);
 newobj.setAttributeNS(xlinkns, "xlink:href", href);
 return newobj;
}

function new_tspan(id,fillcolor){
 var newobj=svgdoc.createElementNS(svgns,"tspan");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"fill",fillcolor);
 return newobj;
}

function new_circle(id,x,y,r,classid){
 var newobj=svgdoc.createElementNS(svgns,"circle");
 newobj.setAttributeNS(null,"id",id);
 newobj.setAttributeNS(null,"cx",x);
 newobj.setAttributeNS(null,"cy",y);
 newobj.setAttributeNS(null,"r",r);
 newobj.setAttributeNS(null,"class",classid);
 return newobj;
}