var t = "\\some\\route\\here";
t = t.substr(0, t.lastIndexOf("\\"));
alert(t);
此外,还需要将字符串中的 \字符加倍,因为它们用于转义特殊字符。
更新
由于这种方法经常被证明对其他人有用,这里有一个片段示例..。
// the original string
var t = "\\some\\route\\here";
// remove everything after the last backslash
var afterWith = t.substr(0, t.lastIndexOf("\\") + 1);
// remove everything after & including the last backslash
var afterWithout = t.substr(0, t.lastIndexOf("\\"));
// show the results
console.log("before : " + t);
console.log("after (with \\) : " + afterWith);
console.log("after (without \\) : " + afterWithout);