javascript - 如何检查字符串是否包含子字符串？ [重复](How do I check if string contains substring? [duplicate])

Question

This question already has an answer here:(这个问题在这里已有答案：)

• How to check whether a string contains a substring in JavaScript?(如何检查字符串是否包含JavaScript中的子字符串？) 3 answers(3个答案)

I have a shopping cart that displays product options in a dropdown menu and if they select "yes", I want to make some other fields on the page visible.(我有一个购物车，在下拉菜单中显示产品选项，如果他们选择“是”，我想让页面上的其他字段可见。)

The problem is that the shopping cart also includes the price modifier in the text, which can be different for each product.(问题是购物车还包括文本中的价格修饰符，每个产品可能不同。)

The following code works:(以下代码有效：)

$(document).ready(function() {
    $('select[id="Engraving"]').change(function() {
        var str = $('select[id="Engraving"] option:selected').text();
        if (str == "Yes (+ $6.95)") {
            $('.engraving').show();
        } else {
            $('.engraving').hide();
        }
    });
});

However I would rather use something like this, which doesn't work:(但是，我宁愿使用这样的东西，这是行不通的：)

$(document).ready(function() {
    $('select[id="Engraving"]').change(function() {
        var str = $('select[id="Engraving"] option:selected').text();
        if (str *= "Yes") {
            $('.engraving').show();
        } else {
            $('.engraving').hide();
        }
    });
});

I only want to perform the action if the selected option contains the word "Yes", and would ignore the price modifier.(如果所选选项包含单词“是”，我只想执行操作，并忽略价格修饰符。)

  ask by Jordan Garis translate from so

Answer 1

Like this:(像这样：)

if (str.indexOf("Yes") >= 0)

...or you can use the tilde operator:(...或者你可以使用代字号运算符：)

if (~str.indexOf("Yes"))

This works because indexOf() returns -1 if the string wasn't found at all.(这是有效的，因为如果根本找不到字符串， indexOf()将返回-1 。)

Note that this is case-sensitive.(请注意，这是区分大小写的。)

If you want a case-insensitive search, you can write(如果您想要不区分大小写的搜索，可以编写)

if (str.toLowerCase().indexOf("yes") >= 0)

Or,(要么，)

if (/yes/i.test(str))