JS按字节截取字符长度实例_javascript技巧

<P><BR>*<BR>&nbsp;* 处理过长的字符串，截取并添加省略号<BR>&nbsp;* 注：半角长度为1，全角长度为2<BR>&nbsp;* <BR>&nbsp;* pStr:字符串<BR>&nbsp;* pLen:截取长度<BR>&nbsp;* <BR>&nbsp;* return: 截取后的字符串<BR>&nbsp;*<BR><div class="codetitle"><span><a style="CURSOR: pointer" data="30021" class="copybut" id="copybut30021" onclick="doCopy('code30021')"><U>复制代码</U></a></span> 代码如下:</div><div class="codebody" id="code30021"><BR>function autoAddEllipsis(pStr, pLen) { <br><br>&nbsp;&nbsp;&nbsp; var _ret = cutString(pStr, pLen); <BR>&nbsp;&nbsp;&nbsp; var _cutFlag = _ret.cutflag; <BR>&nbsp;&nbsp;&nbsp; var _cutStringn = _ret.cutstring; <br><br>&nbsp;&nbsp;&nbsp; if ("1" == _cutFlag) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return _cutStringn + "..."; <BR>&nbsp;&nbsp;&nbsp; } else { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return _cutStringn; <BR>&nbsp;&nbsp;&nbsp; } <BR>} <BR></div> <BR>*<BR>&nbsp;* 取得指定长度的字符串<BR>&nbsp;* 注：半角长度为1，全角长度为2<BR>&nbsp;* <BR>&nbsp;* pStr:字符串<BR>&nbsp;* pLen:截取长度<BR>&nbsp;* <BR>&nbsp;* return: 截取后的字符串<BR>&nbsp;*<BR><div class="codetitle"><span><a style="CURSOR: pointer" data="21735" class="copybut" id="copybut21735" onclick="doCopy('code21735')"><U>复制代码</U></a></span> 代码如下:</div><div class="codebody" id="code21735"><BR>function cutString(pStr, pLen) { <br><br>&nbsp;&nbsp;&nbsp; // 原字符串长度 <BR>&nbsp;&nbsp;&nbsp; var _strLen = pStr.length; <br><br>&nbsp;&nbsp;&nbsp; var _tmpCode; <br><br>&nbsp;&nbsp;&nbsp; var _cutString; <br><br>&nbsp;&nbsp;&nbsp; // 默认情况下，返回的字符串是原字符串的一部分 <BR>&nbsp;&nbsp;&nbsp; var _cutFlag = "1"; <br><br>&nbsp;&nbsp;&nbsp; var _lenCount = 0; <br><br>&nbsp;&nbsp;&nbsp; var _ret = false; <br><br>&nbsp;&nbsp;&nbsp; if (_strLen &lt;= pLen/2) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _cutString = pStr; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _ret = true; <BR>&nbsp;&nbsp;&nbsp; } <br><br>&nbsp;&nbsp;&nbsp; if (!_ret) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; for (var i = 0; i &lt; _strLen ; i++ ) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (isFull(pStr.charAt(i))) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _lenCount += 2; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } else { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _lenCount += 1; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } <br><br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (_lenCount &gt; pLen) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _cutString = pStr.substring(0, i); <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _ret = true; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; break; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } else if (_lenCount == pLen) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _cutString = pStr.substring(0, i + 1); <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _ret = true; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; break; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } <BR>&nbsp;&nbsp;&nbsp; } <br><br>&nbsp;&nbsp;&nbsp; if (!_ret) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _cutString = pStr; <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _ret = true; <BR>&nbsp;&nbsp;&nbsp; } <br><br>&nbsp;&nbsp;&nbsp; if (_cutString.length == _strLen) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _cutFlag = "0"; <BR>&nbsp;&nbsp;&nbsp; } <br><br>&nbsp;&nbsp;&nbsp; return {"cutstring":_cutString, "cutflag":_cutFlag}; <BR>} <BR></div> <BR>*<BR>&nbsp;* 判断是否为全角<BR>&nbsp;* <BR>&nbsp;* pChar:长度为1的字符串<BR>&nbsp;* return: tbtrue:全角<BR>&nbsp;*&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; false:半角<BR>&nbsp;*</P> <P><div class="codetitle"><span><a style="CURSOR: pointer" data="99709" class="copybut" id="copybut99709" onclick="doCopy('code99709')"><U>复制代码</U></a></span> 代码如下:</div><div class="codebody" id="code99709"> <BR>function isFull (pChar) {<BR>&nbsp; for (var i = 0; i &lt; pChar.strLen ; i++ ) {&nbsp;&nbsp;&nbsp;&nbsp; <BR>&nbsp;&nbsp;&nbsp; if ((pChar.charCodeAt(i) &gt; 128)) { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return true; <BR>&nbsp;&nbsp;&nbsp; } else { <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return false; <BR>&nbsp;&nbsp;&nbsp; }<BR>}<BR>}<BR></div><BR>用例：<BR><div class="codetitle"><span><a style="CURSOR: pointer" data="39229" class="copybut" id="copybut39229" onclick="doCopy('code39229')"><U>复制代码</U></a></span> 代码如下:</div><div class="codebody" id="code39229"><BR>testStr = "测试1字符串";<BR>autoAddEllipsis(testStr, 1); // "测..."<BR>autoAddEllipsis(testStr, 2); // "测..."<BR>autoAddEllipsis(testStr, 3); // "测..."<BR>autoAddEllipsis(testStr, 4); // "测试..."<BR>autoAddEllipsis(testStr, 5); // "测试1..."<BR>autoAddEllipsis(testStr, 6); // "测试1..."<BR>autoAddEllipsis(testStr, 7); // "测试1字..."<BR></div></P>