一个非常高效的js的trim截取字符串-原生方法-正则表达式
第一种非常高效的原生方法：
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<html><head><script type = "text/javascript">// prototype trim method ,a very effective method of to trim a String String.prototype.trim = function() { return this.replace(/^\s\s*/, '').replace(/\s\s*$/, ''); } function tip(){var tipMessage = document.getElementById("test").value;alert(tipMessage.trim().length);}</script></head><body><input type="text" name = "test" style="width:100px"><input type="button" onclick="tip()" value="submit"></body></html>??
第二种方法更高效，直逼二进制,这不是牛人写的，这是神写的！
附上js三元运算：
var test = document.getElementById("test").value; ?
var flag = ?(test=="a")?"a":( (test=="b")?"b":(test=="c"?"c":"other"));
alert(flag);
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<html><head><script type = "text/javascript">// prototype trim method ,a very effective method of to trim a String String.prototype.trim = function() { var str = this, whitespace = ' \n\r\t\f\x0b\xa0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000';for (var i = 0,len = str.length; i < len; i++) { if (whitespace.indexOf(str.charAt(i)) === -1) { str = str.substring(i); break; } } for (i = str.length - 1; i >= 0; i--) { if (whitespace.indexOf(str.charAt(i)) === -1) { str = str.substring(0, i + 1); break; } } return whitespace.indexOf(str.charAt(0)) === -1 ? str : ''; } function tip(){var tipMessage = document.getElementById("test").value;alert(tipMessage.trim().length);}</script></head><body><input type="text" name = "test" style="width:100px"><input type="button" onclick="tip()" value="submit"></body></html>