<script language="JavaScript">
<!--
function calculate() {
var x= document.Form.x.value
var y = document.Form.y.value
if(x> 0 && y> 0){
var final = x/(y/100*y/100)
document.Form.answer.value = final
if(final < a){
document.Form.meaning.value = "A"
}
if(final > a && final < b){
document.Form.meaning.value = "B"
}
if(final > b && final < c){
document.Form.meaning.value = "C"
}
if(final > d){
document.Form.meaning.value = "D"
}
}
else{
alert("Please Fill form in correctly")
}
}
//-->
</script>
<div class=form2>
<form name="Form">
x: <input type="text" name="x" size="10"><br />
y: <input type="text" name="y" size="10"><br />
<input type="button" value="Calculate" onClick="calculate()"><br />
Answer: <input type="text" name="answer" size="10"><br />
This Means: <input type="text" name="meaning" size="25"><br />
<input type="reset" value="Reset" />
</form>
</div>
我使用上面的方法根据人们的输入 X 和 Y 进行计算...
我得到了想要的答案,但是给出了一长串小数位。
我正在寻找一种方法,将每个答案四舍五入到最多 2 位小数。
任何帮助将不胜感激:-)
最佳答案
Math.ceil()
将向上舍入,Math.floor()
将向下舍入到最接近的整数。
您需要将答案增加 100 倍以进行四舍五入,然后将其除以 100 以返回到小数。
此外,您的代码中有很多内容不遵循现代的最佳实践和标准,并且您的 if
逻辑也存在一些问题。
有关详细信息,请参阅内嵌评论:
window.addEventListener("DOMContentLoaded", function(){
// Always get references to the elelements themselves, not property values.
// That way, if you decide you need to access another property somewhere else
// you don't have to re-scan the DOM for the same element. Also, access elements
// using modern standards.
var x= document.querySelector("input[name='x']");
var y= document.querySelector("input[name='y']");
var ans= document.getElementById("answer");
var m = document.getElementById("meaning");
var btn = document.getElementById("calc");
// Set up button click event handler here, in the JavaScript, not in the HTML
btn.addEventListener("click", calculate);
function calculate() {
// Next, always trim off any possible leading or trailing spaces from user input
var xVal = x.value.trim();
var yVal = y.value.trim();
if(xVal > 0 && yVal > 0){
var final = xVal/(yVal/100*yVal/100);
console.log("Answer = " + final);
// First, multiply answer by 100
final = final * 100;
console.log("Answer times 100 = " + final);
// Next, round answer up to nearest whole number
final = Math.ceil(final);
console.log("Answer times 100, rounded up to nearest whole number = " + final);
// Now, divide by 100 to go back to decimals
final = final / 100;
console.log("Answer divided back by 100 = " + final);
ans.textContent = final;
// These should be else if, not one if after another since only
// one of the conditions will be true.
if(final < a){
m.textContent = "A"
} else if(final > a && final < b){
m.textContent = "B"
} else if(final > b && final < c){
m.textContent = "C"
} else if(final > d){
m.textContent = "D"
}
} else{
alert("Please Fill form in correctly")
}
}
});
.left {
float:left;
width:100px;
}
.results {
margin-top:1em;
}
.after {
clear:both;
margin-top:2em;
}
<div class=form2>
<form name="Form">
<!-- The text that accompanies the fields should be <label> elements
for better accessibility and for easier styling. -->
<label for="x" class="left">x: </label><input type="text" name="x" id="x" size="10"><br>
<label for="y" class="left">y: </label><input type="text" name="y" id="y" size="10">
<!-- Don't use inline HTML event handling attributes.
Do you JavaScript separately. -->
<div><input type="button" value="Calculate" id="calc"></div>
<!-- Don't use form fields for displaying data. -->
<div class="results">
<span class="left">Answer: </span><span id="answer"></span><br>
<span class="left">This Means: </span><span id="meaning"></span>
</div>
<div class="after">
<input type="reset" value="Reset">
</div>
</form>
</div>
关于javascript - 将答案四舍五入到小数位,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45267223/