JS detects whether form data changes when leaving or refreshing a page _javascript tips

This article describes how JS detects whether form data changes when it leaves or refreshes the page. Share to everyone for your reference, specific as follows:

function Formisdirty (form) {for (var i = 0; i < form.elements.length; i++) {var element = Form.elements[i];
    var type = Element.type;
      if (type = = CheckBox | | | | type = = "Radio") {if (element.checked!= element.defaultchecked) {return true; } else if (type = = "hidden" | | | = = = "Password" | | | type = = "Text" | | | = = = "TextArea") {if Elem
      Ent.value!= element.defaultvalue) {return true; ' Else if (type = = ' Select-one ' | | | | ' = = = ' Select-multiple ') {for (var j = 0; J < Element.options.len Gth
        J + +) {if (element.options[j].selected!= element.options[j].defaultselected) {return true;
}}} return false;
  } window.onbeforeunload = function (e) {e = e | | window.event; if (Formisdirty (document.forms["Someform"])) {//IE and Firefox if (e) {e.returnvalue = "Sorry, the page data has been modified, has not been saved, indeed Are you set to refresh or leave this page?
    "; //Safari browser return "Sorry, the page data has been modified, has not been saved,Are you sure you want to refresh or leave this page?
  ";

 }
};

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I hope this article will help you with JavaScript programming.