Question

可能重复：
How do you pass a variable to a Regular Expression JavaScript?

我需要帮助才能解决问题，因为代码失败了 numLength [0]：

<html>
<body>

<script type="text/javascript">
function xyz(){
var predefLength = "5,5";
var number = "20";
var numLength = predefLength.split(",");
var result = /^[-+]?\d{0,numLength[0]}(\.\d{0,numLength[1]})?$/.test(number);
document.write(result);
}
</script>

</body>
</html>

任何帮助都会受到赞赏。

Answer 1

使用RegExp - 构造函数，例如：

var pattern = new RegExp('pattern as a string', 'flags as a string');

或者：

var result = new RegExp('^[-+]?\d{0,' + numLength[0] + '}(\.\d{0,' + numLength[1] + '})?$').test(number);

Answer 2

试试这个：

<script type="text/javascript">
function xyz(){
var predefLength = "5,5";
var number = "20";
var numLength = predefLength.split(",");

var pattern = new RegExp('^[-+]?\\d{0,'+numLength[0]+'}(\\.\\d{0,'+numLength[1]+'})?$');
var result = pattern.test(number);
document.write(result);
}
</script>

Answer 3

numLength [0]是5.我们不能在正则表达式中添加变量的评估。下面的代码返回true。

var result = /^[-+]?\d{0,x}(\.\d{0,5})?$/.test(number);

如何在javascript中将变量传递给正则表达式

3 个答案: