fixbug

stmms-web/src/main/webapp/static/mark-new/js/modules/mark-board.js

@@ -335,7 +335,7 @@ MarkBoard.prototype.onStepSelect = function(event, context, stepNumber) {
         this.togglePopover(false);
 
         this.currentStep = this.stepList[stepNumber - 1];
-        if (this.currentStep.score == undefined) {
+        if (this.currentStep.score == undefined || isNaN(this.currentStep.score)) {
             this.currentStep.score = '';
         }
         dom = this.stepBoard.stepArray[stepNumber - 1];