codemirror: cancel next AJAX request when before checking source code

I am not 100% sure this really change anything, codemirror have something with async: true that I have not checked

bt5/erp5_code_mirror/SkinTemplateItem/portal_skins/erp5_code_mirror/code_mirror_support.xml

@@ -451,12 +451,18 @@
    is_maximized = true;\n
  }\n
 \n
+ var timer = 0;\n
  function checkPythonSourceCode(text, updateLinting, options, cm) {\n
    checker_parameters = {code: text};\n
 <dtml-if bound_names>\n
    checker_parameters[\'bound_names\'] = <dtml-var name="bound_names">;\n
    checker_parameters[\'params\'] = $(\'input[name="params"]\').val();\n
 </dtml-if>\n
+   if (timer) {\n
+     window.clearTimeout(timer);\n
+     timer = 0;\n
+   }\n
+   timer = window.setTimeout(function() {\n
      $.post(\n
        \'&dtml-portal_url;/ERP5Site_checkPythonSourceCodeAsJSON\',\n
        {\'data\': JSON.stringify(checker_parameters)},\n
@@ -472,9 +478,9 @@
               severity: message.type\n
             });\n
           }\n
-\n
           updateLinting(cm, found);\n
      });\n
+   }, 500); // this timeout can depend on the source code len length\n
  }\n
 \n
  var mode = "&dtml-mode;";\n