js替換字串中所有指定的字元(實現代碼)，js字串

js替換字串中所有指定的字元(實現代碼)，js字串

第一次發現JavaScript中replace() 方法如果直接用str.replace("-","!") 只會替換第一個匹配的字元.
而str.replace(/\-/g,"!")則可以全部替換掉匹配的字元(g為全域標誌)。

replace()

The replace() method returns the string that results when you replace text matching its first argument
(a regular expression) with the text of the second argument (a string).
If the g (global) flag is not set in the regular expression declaration, this method replaces only the first
occurrence of the pattern. For example,

var  s = "Hello. Regexps are fun." ;s = s.replace(/\./, "!" ); // replace first period with an exclamation pointalert(s);

produces the string “Hello! Regexps are fun.” Including the g flag will cause the interpreter to
perform a global replace, finding and replacing every matching substring. For example,

var  s = "Hello. Regexps are fun." ;s = s.replace(/\./g, "!" ); // replace all periods with exclamation pointsalert(s);

yields this result: “Hello! Regexps are fun!”

所以可以用以下幾種方式：

string.replace(/reallyDo/g, replaceWith);

string.replace(new RegExp(reallyDo, 'g'), replaceWith);

string：字串運算式包含要替代的子字串。
reallyDo：被搜尋的子字串。

replaceWith：用於替換的子字串。

Js代碼

<script type="text/javascript"> String.prototype.replaceAll = function(reallyDo, replaceWith, ignoreCase) {   if (!RegExp.prototype.isPrototypeOf(reallyDo)) {     return this.replace(new RegExp(reallyDo, (ignoreCase ? "gi": "g")), replaceWith);   } else {     return this.replace(reallyDo, replaceWith);   } } </script> 

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