JavaScript-使用“选中/未选中的复选框"作为"IF ELSE条件声明"； [英] JavaScript - Using "checked/unchecked checkbox" as "IF ELSE condition statement"
问题描述
现在，我想将"check/unchecked"复选框用作"IF condition statement".
Now I want to use "check/unchecked checkbox" as "IF condition statement".
示例:我想根据您击中的音符制作和弦分析器.当您选中复选框上的音符(或某些音符)，然后按这些复选框下方的按钮时，段落元素应告诉您您所弹奏的和弦.但是我在 if("error")语句上写的错误.如何解决?
Example: I want to make a chord analyzer based on the note(s) you hit. When you check a note (or some notes) on checkbox, then press the button under those checkboxes, the paragraph element should tell you about what chord you hit. But there's error on my writing at if ("error") statement. How to fix it?
这是我的代码:
<!doctype html>
<html>
<head>
<script>
function fungsi() {
var c = document.getElementById("C").checked;
var e = document.getElementById("E").checked;
var f = document.getElementById("F").checked;
var g = document.getElementById("G").checked;
if (c.checked = true &&
e.checked = true &&
g.checked = true &&
f.checked = false) {
document.getElementById("chord").innerHTML = "C Chord";
} else if (c.checked = true &&
f.checked = true &&
g.checked = false &&
e.checked = false) {
document.getElementById("chord").innerHTML = "F Chord";
} else {
alert("Under Development!");
}
}
</script>
</head>
<body>
<form>
Note(s) That You Hit:<br>
<input type=checkbox id="C">C<br>
<input type=checkbox id="E">E<br>
<input type=checkbox id="F">F<br>
<input type=checkbox id="G">G
</form>
<button type=button onclick="fungsi()">The Chord Is</button>
<p id="chord"></p>
</body>
</html>
推荐答案
if(c.checked = true)和类似内容应简单地 if(c.checked)
if(f.checked = false)和类似的东西应该简单地 if(！f.checked).
if (f.checked=false) and similar should be simply if (!f.checked).
如果需要，可以执行 if(c.checked == true)或 if(c.checked === true)，类似地执行if(f.checked == false)或 if(f.checked === false)，但这在绝大多数情况下都是毫无意义的.您已经有一个布尔值.只需 if(c.checked)和 if(！f.checked)就足够了.
If you want, you can do if (c.checked==true) or if (c.checked===true), and similarly if (f.checked==false) or if (f.checked===false), but it's pointless the vast majority of the time. You already have a boolean value. Just if (c.checked) and if (!f.checked) is sufficient.
例如:
if (c.checked &&
e.checked &&
g.checked &&
!f.checked) {
document.getElementById("chord").innerHTML = "C Chord";
}
分别作为 crclayton点，您要么想要:
var c=document.getElementById("C").checked;
var d=document.getElementById("E").checked;
// ...and so on..., and then:
if (c && e && g && !f)
或
var c=document.getElementById("C"); // <== No .checked
var d=document.getElementById("E"); // <==
// ...and so on..., and then:
if (c.checked &&
e.checked &&
g.checked &&
!f.checked) {
这篇关于JavaScript-使用“选中/未选中的复选框"作为"IF ELSE条件声明"；的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
