var j = 2
alert(i+0+j) 结果 alert：3.
现在解答为什么要加一个0.因为在js里局宴面,如果你直接写+号的话,JS会以为你是把两个字符串相加,就像上面桐纤银的,结果会alert(12),而加上一个0的话,会让它知道这个是在做一个加竖肆法运算而不是拼接字符串。当然
<SCRIPT LANGUAGE="JavaScript"><!--
function change(value1,value2){
var num1 = parseInt(value1)
var num2 = parseInt(value2)
document.getElementById("div1").innerText = num1 + "+" + num2 + "=" + (num1+num2) + "" + num1 + "-" + num2 + "=" + (num1-num2)
}
//-->
</SCRIPT>此颂缺
<input type="text" value="0" id="森辩txt1" onkeyup="change(this.value,document.getElementById('txt2').value)"><br />
<input type="text" value="0" id="txt2" onkeyup="change(document.getElementById('txt1').value,this.value)"><br />
<div id="樱改div1"></div>
<html><head>
<title>小测试</title>
<script language="javascript">
var number1 = 0
var number2 = 0
var n = 0
var total = 0
function getQuestion()
{
//补充代码
number1 = parseInt( Math.random() * 10)
number2 = parseInt(Math.random() * 10)
var n1 虚神陪= document.getElementsByName("n1")
n1(0).value = number1
var n2 = document.getElementsByName("n2")
n2(0).value = number2
var n3 = document.getElementsByName("tresult")
n3(0).value = ""
}
function judge()
差蠢 {
//补充代码
var n3 = document.getElementsByName("tresult")
var number3 = n3(0).value
total ++
if (number3 == number1 + number2)
{
n++
alert("回答正确，正确率是:" + Math.round( parseFloat(n * 100 / total)) + "%")
}
else
{
alert("回答错误，正确答案是:" + (number1 + number2) )
}
getQuestion()
return false
}
</script>
</head>
<body onload="getQuestion()">
<form name="myForm" method="post"瞎弯 action="">
<input type="text" name="n1" disabled="disabled"> <!--禁用输入元素-->
+<input type="text" name="n2" disabled="disabled"> =
<input type="text" name="tresult" id="result">
<input type="submit" name="Submit" value="确定" onclick="return judge()">
</form>
</body>
</html>
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