如何在程序中获得定义的值？ [英] How can I get defined value in my program ?
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问题描述
我将我的书面文字替换为javascript原始语法，以减少写入和节省时间，我接近它，但初学者的许多问题，我已经坚持使用RegExp（）方法，我只知道如何找到像这样的符号\\（或/ \（/
但我不明白为什么代码不起作用只是看我的脚本并回答我。
我尝试过：
< ！DOCTYPE html >
< html >
< 正文 >
< textare a type = text id = in1 行 = 4 >
< / textarea >
< br >
< textarea type = text id = in2 >
< / textarea >
< span class =code-keyword>< script >
function replace（）
{
/ * 此代码将始终显示textarea的底线* /
var ta = document .getElementById（ in1）;
ta.scrollTop = ta.scrollHeight;
var in2 = document .getElementById（ in2）。value;
/ * 这会将所有字符替换为其他字符* /
var replaceChars =
{
d。： document。，
b。： body。，
w \\（ ： write（，
wl \\（： writeln（，
ce\\（： c reateElement（，
ctn \\（：< span class =code-string> createTextNode（，
ac\\（： appendChild（
};
var re = new RegExp （Object.keys（replaceChars）.join（ |）， g）;
var replacement = in2.replace（re， function （match）
{ return replaceChars [match];}）;
document .getElementById（ in1）。value = replacement;
};
/ * 如果我输入第二个textaread.w（）;它返回document.undefined）;我想要document.write（）;如何解决这个未定义的问题* /
< / script >
< / body >
< / html >
解决方案
你的问题是的游行w'\\\（是w（这不在您的数组中。该匹配与RegEx不同。
另一个错误：
d。和b。不匹配d或b后跟一个点，它们匹配d或b后面跟着任何东西，一个字母，一个数字，一个空格...
以下是RegEx文档的链接：
perlre - perldoc.perl.org [ ^
i m replacing my written words to javascript original syntax for less writing and saving time, i m getting near to it but many problems for a beginner, i have stuck here with RegExp() method where i just knew that how to find symbols like "\\(" or /\(/
but i dont understand why the code doesn't work just watch my script and answer me.
What I have tried:
<!DOCTYPE html>
<html>
<body>
<textarea type= "text" id = "in1" rows = "4">
</textarea>
<br>
<textarea type= "text" id = "in2" >
</textarea>
<script>
function replace()
{
/* this code will always show bottom line of textarea */
var ta = document.getElementById("in1");
ta.scrollTop = ta.scrollHeight;
var in2 = document.getElementById("in2").value;
/* this will replace all characters to onother characters */
var replaceChars =
{
"d.": "document.",
"b." : "body.",
"w\\(": "write(",
"wl\\(" : "writeln(",
"ce\\(" : "createElement(",
"ctn\\(" : "createTextNode(",
"ac\\(" : "appendChild("
};
var re = new RegExp(Object.keys(replaceChars).join("|"),"g");
var replaced = in2.replace(re ,function (match)
{return replaceChars[match];});
document.getElementById("in1").value = replaced;
};
/* if i type in second textarea "d.w();" it returns "document.undefined);" and i want "document.write();" how to solve this undefined problem */
</script>
</body>
</html> 解决方案
Your problem is that the march forw\\(isw(which is not in your array. The match is different from the RegEx.
Another bug:
d.andb.are not matching "d" or "b" followed by a point, they match "d" or "b" followed by anything, a letter, a number, a space ...
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
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