禁止网页回退修改

src/modules/HomePage/index.jsx

@@ -40,12 +40,14 @@ class HomePage extends Component {
         })    
         //光标没落到span的时候继续backspace防止页面回退
         $(window).on("keydown",(e)=>{   
-            let ev = e || window.event;   
-            const elem = ev.srcElement || ev.target;
-            const nodeN = elem.nodeName;
-            if(nodeN != "SPAN"){
-                return false;
-            }
+            let ev = e || window.event;  
+            if(ev.keyCode==8){
+                const elem = ev.srcElement || ev.target;
+                const nodeN = elem.nodeName;
+                if(nodeN != "SPAN"){
+                    return false;
+                }
+            } 
         })
     }