js去掉字符串前后空格的五種方法

第一種：循環檢查替換

//供使用者調用function trim(s){return trimRight(trimLeft(s));}//去掉左邊的空白function trimLeft(s){if(s == null) {return '';}var whitespace = new String(' tnr');var str = new String(s);if (whitespace.indexOf(str.charAt(0)) != -1) {var j=0, i = str.length;while (j < i && whitespace.indexOf(str.charAt(j)) != -1){j++;}str = str.substring(j, i);}return str;}//去掉右邊的空白function trimRight(s){if(s == null) return '';var whitespace = new String(' tnr');var str = new String(s);if (whitespace.indexOf(str.charAt(str.length-1)) != -1){var i = str.length - 1;while (i >= 0 && whitespace.indexOf(str.charAt(i)) != -1){i--;}str = str.substring(0, i+1);}return str;}

第二種：正則替換

String.prototype.Trim = function(){return this.replace(/(^s*)|(s*$)/g, '');}String.prototype.LTrim = function(){return this.replace(/(^s*)/g, '');}String.prototype.RTrim = function(){return this.replace(/(s*$)/g, '');}

第三種：使用jquery

$.trim(str)jquery內部實現為：[javascript]function trim(str){return str.replace(/^(s|u00A0)+/,’’).replace(/(s|u00A0)+$/,’’);}

第四種：使用motools

function trim(str){return str.replace(/^(s|xA0)+|(s|xA0)+$/g, ’’);}

第五種：裁剪字符串方式

function trim(str){str = str.replace(/^(s|u00A0)+/,’’);for(var i=str.length-1; i>=0; i--){if(/S/.test(str.charAt(i))){str = str.substring(0, i+1);break;}}return str;}

轉自：http://www.2cto.com/kf/201204/125943.html