js中replace方法的高级替换 js replace 正则替换

第一次发现JavaScript中replace()方法如果直接用str.replace("-","!")只会替换第一个匹配的字符.
而str.replace(/-/g,"!")则可以全部替换掉匹配的字符(g为全局标志)。

replace()

Thereplace()methodreturnsthestringthatresultswhenyoureplacetextmatchingitsfirstargument
(aregularexpression_r)withthetextofthesecondargument(astring).
Iftheg(global)flagisnotsetintheregularexpression_rdeclaration,thismethodreplacesonlythefirst
occurrenceofthepattern.Forexample,

vars="Hello.Regexpsarefun.";s=s.replace(/./,"!");//replacefirstperiodwithanexclamationpointalert(s);

producesthestring“Hello!Regexpsarefun.”Includingthegflagwillcausetheinterpreterto
performaglobalreplace,findingandreplacingeverymatchingsubstring.Forexample,

vars="Hello.Regexpsarefun.";s=s.replace(/./g,"!");//replaceallperiodswithexclamationpointsalert(s);

yieldsthisresult:“Hello!Regexpsarefun!”

所以可以用以下几种方式.：
string.replace(/reallyDo/g,replaceWith);
string.replace(newRegExp(reallyDo,'g'),replaceWith);

string：字符串表达式包含要替代的子字符串。
reallyDo：被搜索的子字符串。
replaceWith：用于替换的子字符串。

1. <scripttype="text/javascript">
2. String.prototype.replaceAll=function(reallyDo,replaceWith,ignoreCase){
3. if(!RegExp.prototype.isPrototypeOf(reallyDo)){
4. returnthis.replace(newRegExp(reallyDo,(ignoreCase?"gi":"g")),replaceWith);
5. }else{
6. returnthis.replace(reallyDo,replaceWith);
7. }
8. }
9. </script>

<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>

另：大全

http://hi.baidu.com/wodemy/blog/item/f1fba016858be210962b4331.html

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