javascript字符串扩展函数,可自定义去掉字符(trim(),ltrim(),rtrim())

/**

* 默认去掉字符串左右所有空白

* example: var str=' ere '; str.trim();

* 如果带参数，则去掉字符串左右指定的字符

* example: var str='-ere-'; str.trim('-');

* */

String.prototype.trim = function(charlist) {

var charlist = charlist || '';

if(charlist == ''){

return this.replace(/(^\s*)|(\s*$)/g, "");

}else{

var reg = '/(^\\'+charlist+'*)|(\\'+charlist+'*$)/g';

return this.replace(eval(reg), "");

}

}

/**

* 默认去掉字符串左边所有空白

* example: var str=' ere '; str.trim();

* 如果带参数，则去掉字符串左边指定的字符

* example: var str='-ere-'; str.trim('-');

* @auth: szguo*/

String.prototype.ltrim = function(charlist) {

var charlist = charlist || '';

if(charlist == ''){

return this.replace(/(^\s*)/g, "");

}else{

var reg = '/(^\\'+charlist+'*)/g';

return this.replace(eval(reg), "");

}

}

/**

* 默认去掉字符串右边所有空白

* example: var str=' ere '; str.trim();

* 如果带参数，则去掉字符串右边指定的字符

* example: var str='-ere-'; str.trim('-');

**/

String.prototype.rtrim = function(charlist) {

var charlist = charlist || '';

if(charlist == ''){

return this.replace(/(\s*$)/g, "");

}else{

var reg = '/(\\'+charlist+'*$)/g';

return this.replace(eval(reg), "");

}

}