Question

html中javascript计算加减乘除，哪位大哥帮帮忙啊！

Answer 1

首先 给每个文本框一个ID
暂且以 one two result来表示

给操作符一个ID :op

var one=document.getElementById("one").value;
var two=document.getElementById("two").value;

var op=document.getElementById("op").value;
switch(op){
case "+":

result.value=parseInt(one)+parseInt(two);

break;
case "-":
result.value=parseInt(one)-parseInt(two);

break;
result.value=parseInt(one)*parseInt(two);

case "*":
break;
result.value=parseInt(one)/parseInt(two);

case "/":
break;
}
细节方面就看你自己了

Answer 2

你好，你需要怎么帮忙啊？是我直接帮你写了？还是教你怎么写？

Answer 3

数量：<input type="text" value="" id="qty" maxLength=9 onblur="Cac();">
单价：<input type="text" value="" id="price" maxLength=9 onblur="Cac();">
金额：<input type="text" value="" id="total" maxLength=9>

<script language="javascript">
Number.prototype.Floats = function (n){if(this!=null){var val=this;var Num=10;var temp,temp1;var k;Num=Math.pow(10,n+1);temp=parseFloat(val);if(temp>=0){k=1;}else {k=-1;};temp=Math.abs(temp);temp1=temp;temp=(temp*Num)%10;temp=Math.round(temp*100)/100;if(temp>=5){temp=(parseFloat(temp1)*Num)-temp;temp=temp+10;temp=temp/Num;}else {temp=(parseFloat(temp1)*Num)-temp;temp=temp/Num;};temp=Math.round(parseFloat(temp)*Math.pow(10,n))/Math.pow(10,n);return isNaN(k*temp)?"":k*temp;}else {return 0;}}
function Cac(){
var d = {};
d.qty = document.getElementById("qty").value;
d.price = document.getElementById("price").value;
d.total = document.getElementById("total").value;

d.qty = (!isNaN(parseFloat(d.qty))) ? parseFloat(d.qty) : 0;
d.price = (!isNaN(parseFloat(d.price))) ? parseFloat(d.price) : 0;
d.total = parseFloat(d.qty*d.price);
d.total = d.total.Floats(2);
document.getElementById("total").value = d.total;
}

</script>

Answer 4

<script language="javascript">
function calc()
{
var op1 = document.all('txtOpNum1').value;
var op2 = document.all('txtOpNum2').value;
var op = document.all('selOp').value;
var result = eval(op1+op+op2);
document.all('txtResult').value = result;
alert(result);
}
</script>

<input type="text" id="txtOpNum1" width="120"/>
<select id="selOp">
<option selected value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select>
<input type="text" id="txtOpNum2" width="120"/>
<input type="button" id="btnCalc" width="60" value="计算" onclick="calc();"/>
<input type="text" id="txtResult" width="120"/>

以上代码直接存为 htm 文件 ，可以运行。