javascript - 在选项中查找值并使用Javascript编辑CSS样式[重复](Finding values in options and editing css style using Javascript [duplicate])

Question

(This question already has answers here) : ((这个问题已经在这里有了答案) ：)

What do querySelectorAll and getElementsBy* methods return? (querySelectorAll和getElementsBy *方法返回什么？) (9 answers) (（9个答案）)

Why doesn't my simple if-statement render false in javascript? (为什么我的简单if语句在javascript中不显示为false？) (2 answers) (（2个答案）)

Incorrect result in JavaScript calculation (2 answers) (JavaScript计算结果不正确 （2个答案）)

Closed 15 hours ago . (15小时前关闭。)

My java script, which I got from a stack overflow question looks like this:(我从堆栈溢出问题中获得的Java脚本如下所示：)

<script type="text/javascript"> function search() { var a = document.getElementByClassName("s1"); var b = a.options[a.selectedIndex].value; if (b = 1) { document.getElementById("vmh").style.visibility = hidden } } </script> and there is a button that activates the function search, but the visibility is not changing(并且有一个按钮可以激活功能搜索，但是可见性没有改变)   ask by Alex translate from so

Answer 1

Your if statement is not comparing values, but is instead assigning a value.(您的if语句不是比较值，而是分配一个值。)

b = 1 assigns 1 to the variable b .(b = 1受让人1到变量b 。) Instead, you'll want to use a comparison operator if (b == 1) .(相反， if (b == 1)需要使用比较运算符。) Secondly, the hidden should be wrapped in quotes.(其次， hidden应用引号引起来。) Currently you are assigning hidden to the visibility property, but hidden does not appear to be a variable.(当前，您正在将hidden分配给visibility属性，但是hidden似乎不是变量。) Instead, you'll do visibility = 'hidden' .(取而代之的是，您将可以看到visibility = 'hidden' 。)