反转 if 语句

Question

我了解 if 条件的工作原理。像这样：

if (condition) {
    block of code to be executed if the condition is true
}

但是我如何反转例如如果语句正确，不要触发这行代码？

if $("span:contains('399')) {
    block of code to be executed if the condition is false
}

Answer 1

if (!condition) {
    block of code to be executed if the condition is false
}