~~~ <div> <span>值1:</span> <input id="input1" type="text /> </div> <div> <span>值2:</span> <input id="input2" type="text /> </div> <div> 和是: <span id="amount”>0</span> </div> var oInp1 = document.getElementById("input1"); var oInp2 = document.getElementById("input2"); var oAmount = document.getElementById("amount"); if("oninput" in oInp1){ oInp1.addEventListener("input",getWord,false); } else { oInp1.onpropertychange = getWord; } if("oninput" in oInp2){ oInp2.addEventListener("input",getWord,false); } else { oInp2.onpropertychange = getWord; } //判断值是否为空,怎么显示,避免出现“NaN” function getWord(){ if(oInp1.value == "" && oInp2.value == "") { oAmount.innerHTML = "0"; } else if (oInp2.value == "") { oAmount.innerHTML = "0"; } else if(oInp1.value == ""){ oAmount.innerHTML = parseInt(oInp2.value) } else { oAmount.innerHTML = parseInt(oInp2.value) + parseInt(oInp1.value); } ~~~