914829451ce180351f7822e72d4cdb25a9d8221e
hiram
  Tue Nov 3 09:43:39 2020 -0800
back to the hidden div method of transmitting jsonData is present refs #21980

diff --git src/hg/hgTracks/wigTrack.c src/hg/hgTracks/wigTrack.c
index 0078b90..ecbaea9 100644
--- src/hg/hgTracks/wigTrack.c
+++ src/hg/hgTracks/wigTrack.c
@@ -1482,30 +1482,33 @@
     jsonWriteObjectEnd(jw);
     fputs(jw->dy->string,trashJson);
     carefulClose(&trashJson);
     mouseOverIdx = -1;
     freez(&mouseOverData);
     if (! beenHereDoneThat )
         {
         hPrintf("<div id='mouseOverLine' class='mouseOverHighlight'></div>\n");
         hPrintf("<div id='mouseOverContainer' class='wigMouseOver'>\n");
         hPrintf("  <span id='mouseOverText' class=wigMouseOverValue'>\n");
         hPrintf("  </span>\n");
         hPrintf("</div>\n");
 // hPrintf("<div id='mouseDbg'><span id='debugMsg'><p>. . . mouseDbg</p></span></div>\n");
         beenHereDoneThat = TRUE;
         }
+    // hidden element to pass along jsonData file name and also the trigger
+    // that this track has data to display.
+    hPrintf("<div id='mouseOver_%s' name='%s' class='hiddenText mouseOverData' jsonData='%s'></div>\n", tg->track, tg->track, jsonData.forCgi);
     }
 else
     wigMapSelf(tg, hvg, seqStart, seqEnd, xOff, yOff, width);
 }
 
 struct preDrawContainer *wigLoadPreDraw(struct track *tg, int seqStart, int seqEnd, int width)
 /* Do bits that load the predraw buffer tg->preDrawContainer. */
 {
 /* Just need to do this once... */
 if (tg->preDrawContainer)
     return tg->preDrawContainer;
 
 struct wigItem *wi;
 double pixelsPerBase = scaleForPixels(width);
 double basesPerPixel = 1.0;