使用js替換字串中所有指定字元的實作方法

第一次發現JavaScript中replace() 方法如果直接用str.replace("-","!") 只會取代第一個符合的字元.

而str.replace(/\-/g,"!")則可以全部替換掉符合的字元(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 patternence 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,## 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：字串表達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程式碼

<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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