statements_do这段代码为什么不执行呢？

Blockly.Blocks['speech_recognition'] = {
init: function() {
this.appendValueInput("condition")
.setCheck(null)
.appendField("if")
.appendField("you")
.appendField("hear");
this.appendStatementInput("do")
.setCheck(null)
.appendField("do");
this.setInputsInline(false);
this.setPreviousStatement(true, null);
this.setNextStatement(true, null);
this.setColour(230);
this.setTooltip("");
this.setHelpUrl("");
}
};
Blockly.JavaScript['speech_recognition'] = function(block) {
var value_condition = Blockly.JavaScript.valueToCode(block, 'condition', Blockly.JavaScript.ORDER_ATOMIC);
var statements_do = Blockly.JavaScript.statementToCode(block, 'do');
var SpeechRecognition = window.SpeechRecognition || window.webkitSpeechRecognition;
var recognition = new SpeechRecognition();
recognition.continuous = true;
recognition.onend = function() {
return;
recognition.start();
}
recognition.onresult = function(event) {
var current = event.resultIndex;
var transcript = event.results[current][0].transcript;
var code="if("+transcript+"=="+value_condition+"){\n"+statements_do+";\n}";
}
recognition.start();
return code;

};

打上debugger看看