javascript语言精粹-笔记

walkDOM

function walkTheDOM(node, func) { func(node); node = node.firstChild; while (node) { walkTheDOM(node, func); node = node.nextSibling; } }

getElementsByClassName

function getElementsByClassName(className) { var results = []; walkTheDOM(document.body, function (node) { var a, c = node.className, i; if (c) { a = c.split(' '); for (i = 0; i < a.length; i += 1) { if (a[i] === className) { results.push(node); break; } } } }); return results; }

第六章

6.5 判断是不是数组

var is array = function (value) { return value && typeof value.splice === 'function' && typeof value.length=== 'number' && typeof value === 'object' && ! (value.propertyIsEnumerable ('length')); };

写一个Reduce

Array. method ('reduce', function(f,value) { var i; for （i=0;i<this.length; i +=1) { value = f(this [i], value); } return value; })

第七章正则表达式

7.1 匹配url的正则

var parse_url =/^ (?: ([A-Za-z]+) :)? (\/{0,3}) ( [0-9.\-A-Za-z]+)(?:: (d+))? (?:\/([^?#]*))?(?:\? ([^#]*))? (?:#(.*))?$/; var url ="http://www.ora.com: 80/goodparts?q#fragment";

匹配数字的reg

var parse_number =/^-?\d+(?:\.\d*)? (?:e [+\-]?\dt)?S/i;

var test= function (num) { document.writeln(parse number.test (num) ); }; true test ("1"); false test ('number'); true test('98.6"); false test ('132.21.86.100'); true test ('123.45E-67'); false test ('123.45D-67');

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