javascript - Userscript works in Firefox, but Chrome gives: Uncaught TypeError: Cannot read property 'length' of null -

i tried run this script in chrome, doesn't work.

just error cannot read property 'length' of null appears.

if($("div.diashow").length>0&&$("div.diashow.list").length==0){      jquery.ajaxsetup({async:false});      var objcontent = $("#objectcontent");      $("span.prev").remove();     $("span.next").remove();     $("p.next").remove();      $("div.screen img").unwrap();      var numofslides = parseint($("span.volume").text().substr(11));          for(var i=2;i<=numofslides;i++){          $.get("document.url"+"?_slidenumber="+i, function(data) {              var slidescanvas = $("div.slidescanvas",data);              $("span.prev",slidescanvas).remove();             $("span.next",slidescanvas).remove();             $("p.next",slidescanvas).remove();              $("div.screen img",slidescanvas).unwrap();              objcontent.append(slidescanvas);                     });            }         } 

i tried fix myself, limited javascript knowledge, wasn't successful. why script not work in chrome? works in firefox.

sample target page script.

that userscript uses @require load jquery, thing.
however, straight chrome not support @require (nor of greasemonkey's marvelous features).

so, use script as-is in chrome, smart thing install , use tampermonkey. tampermonkey has number of advantages on straight chrome userscript, in ease of use, compatibility, , power.

if, not want use tampermonkey, rewrite script use this cross-browser technique loading jquery.