JS Implementation Ctrl + V paste pictures or screenshots

Browser Environment: Google Chrome

1.ctrl+v paste pictures are listening paste time implementation, the copied data are present clipboarddata below, although the print display data length is 0, but still can get the data

2. Print Clipboarddata.items discovery is a datatransferitem.

3.DataTransferItem there is a getasfile () method that can obtain the file

Document.addeventlistener ('Paste', Function (Event) {Console.log (Event); varIschrome =false; if(Event. clipboarddata | |Event. Originalevent) {            //Some versions of Chrome are using Event.originalevent            varClipboarddata = (Event. clipboarddata | |Event. Originalevent.clipboarddata); if(clipboarddata.items) {//For Chrome                varItems =Clipboarddata.items, Len.=Items.length, Blob=NULL; Ischrome=true;  for(vari =0; i < Len; i++) {Console.log (items[i]); if(Items[i].type.indexof ("Image") !== -1) {                        //Getasfile () This method is only living standard Firefox IE11 does not supportBlob =Items[i].getasfile (); }                }            }        }    })

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You can get to the Blob object at this time, you can choose to display on the page, you can also choose to send to the background

3.1 Displaying pictures

3.1.1 Executes the following code, using the Blob object to display

  var bloburl=Url.createobjecturl (BLOB);       document.getElementById ("imgnode"). Src=bloburl;

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3.1.2 Using base64 code display, need to use FileReader

Reader.onload = function (event) {                        //  Event.target.result is the BASE64 encoded string for the picture                        varevent. Target.result;                        document.getElementById ("imgnode"). src=base64_str;                    }                    Reader.readasdataurl (BLOB);

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3.2 Uploading to the background

3.2.1 Generates Formdata, where Formdata is generated and requires the help of a canvas

//with canvas, generate Formdata                    varCanvas = document.createelement ('Canvas'); varDataurl = Canvas.todataurl ('Image/jpeg',0.5); varFD =NewFormData (document.forms[0]); Fd.append ("The_file"Blob'Image.png'); //Create a XMLHttpRequest object                    varXHR =NewXMLHttpRequest (); Xhr.open ('POST','/image' ); Xhr.onload=function () {if(Xhr.readystate = = =4 ) {                            if(Xhr.status = = = $ ) {                                vardata =Json.parse (Xhr.responsetext);                            Console.log (data); } Else{console.log (xhr.statustext);                    }                        };                    }; Xhr.onerror=function (e) {console.log (xhr.statustext); } xhr.send (FD);

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3.3 Full Code

The complete code is as follows

<! DOCTYPE html>"en">"UTF-8"> <title>Title</title> <style>Body {display:-webkit-Flex;            Display:flex; -webkit-justify-Content:center; Justify-Content:center; }    </style>"width:300px;height:100px; border:1px Solid"> ""Id="Imgnode"></div></body><script>Document.addeventlistener ('Paste', Function (Event) {Console.log (Event); varIschrome =false; if(Event. clipboarddata | |Event. Originalevent) {            //Some versions of Chrome are using Event.originalevent            varClipboarddata = (Event. clipboarddata | |Event. Originalevent.clipboarddata); if(clipboarddata.items) {//For Chrome                varItems =Clipboarddata.items, Len.=Items.length, Blob=NULL; Ischrome=true;  for(vari =0; i < Len; i++) {Console.log (items[i]); if(Items[i].type.indexof ("Image") !== -1) {                        //Getasfile () This method is only living standard Firefox IE11 does not supportBlob =Items[i].getasfile (); }                }                if(blob!==NULL){                    varBloburl=Url.createobjecturl (BLOB); //Blob Object Displaydocument.getElementById ("Imgnode"). src=Bloburl; varReader =NewFileReader (); //Base64 Code Display                   /*reader.onload = function (event) {//Event.target.result is the BASE64 encoded string for the picture                        var base64_str = Event.target.result;                    document.getElementById ("Imgnode"). Src=base64_str; } reader.readasdataurl (BLOB);*/                    //with canvas, generate Formdata                    varCanvas = document.createelement ('Canvas'); varDataurl = Canvas.todataurl ('Image/jpeg',0.5); varFD =NewFormData (document.forms[0]); Fd.append ("The_file"Blob'Image.png'); //Create a XMLHttpRequest object                    varXHR =NewXMLHttpRequest (); Xhr.open ('POST','/image' ); Xhr.onload=function () {if(Xhr.readystate = = =4 ) {                            if(Xhr.status = = = $ ) {                                vardata =Json.parse (Xhr.responsetext);                            Console.log (data); } Else{console.log (xhr.statustext);                    }                        };                    }; Xhr.onerror=function (e) {console.log (xhr.statustext);                } xhr.send (FD); }            }        }    })</script>
JS Implementation Ctrl + V paste pictures or