simple backspace handled

dist/assets/a-doc-editor2.js

@@ -171,7 +171,6 @@ var ADocEditor = function (customConfig) {
     }
 
     function reRenderCanvas() {
-        console.clear()
         if (isRendering) return
         let pageIndex = 0
         if (!pageList.length) {
@@ -395,9 +394,14 @@ var ADocEditor = function (customConfig) {
         }
 
         function keydownHandler(e) {
+            console.clear()
             if (e.key == 'Backspace') {
                 if (caretData.index == 0) {
-
+                    let activeDataIndex = dataList.findIndex( item => item.id==caretData.activeData.id )
+                    if (activeDataIndex>0){
+                        caretData.activeData = dataList[activeDataIndex-1]
+                        caretData.index = caretData.activeData.plainContent.length
+                    }
                 } else {
                     caretData.activeData.plainContent = caretData.activeData.plainContent.slice(0, caretData.index - 1) + caretData.activeData.plainContent.slice(caretData.index)
                     caretData.activeData.formatedText.splice(caretData.index - 1, 1)