正则表达式将查找一个单词(在word边界上)，该单词将以冒号 : 作为前缀和后缀。

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var input = "I went to :Rome: last night, now I'm in :Florence:";
var regex = /(?:\:)\b(\w*)\b(?=\:)/g
var arr = []
while (m = regex.exec(input)) arr.push(m[1]);
alert(arr)

​

编辑的

由于JavaScript风格的RegExp不支持许多特性，我建议将regex替换为：

var input = "I went to :Rome: last night, now I'm in :Florence:";
var regex = /:([\w]+):/g
var replaced = input.replace(regex, "$1")

您可以使用：

var arr = [],
    re = /:([^ :]+):/g,
    input = "I went to :Rome: last night, now I'm in :Florence:";