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js 一些小技巧 2

a js 的一些小技巧

(1)传入一个表单控件(如input输入框,按钮)获取所在的form

var getForm= function (formElement) {  var $that=$(formElement).parent();  var max=6;//limit the depth  var fieldsetElement=null;//form element  var tagName=null;//html tag name  while((fieldsetElement=$that.get(0))&&fieldsetElement.tagName!==undefined&&(tagName=fieldsetElement.tagName.toLowerCase())!=='form'&&max>0){   if(tagName==='fieldset'){//html5 new tag    $that=$(fieldsetElement.form);    break;   }   $that=$that.parent();   max--;  }  console.log(max);  return $that; };

完整示例 :

<!DOCTYPE html> <html> <head lang="en">  <meta charset="UTF-8">  <script type="text/javascript" src="js/jquery-1.11.1.js"></script>  <title></title>  <script type="text/javascript">   var getForm = function (formElement) {    var $that = $(formElement).parent();    var max = 6;//limit the depth    var fieldsetElement = null;//form element    var tagName = null;//html tag name    while ((fieldsetElement = $that.get(0)) && fieldsetElement.tagName !== undefined && (tagName = fieldsetElement.tagName.toLowerCase()) !== 'form' && max > 0) {     if (tagName === 'fieldset') {//html5 new tag      $that = $(fieldsetElement.form);      break;     }     $that = $that.parent();     max--;    }    console.log(max);    return $that;   };   var getForm22 = function (self) {    $form = getForm(self);    console.log($form);   }  </script> </head> <body> <div id="login-content">  <form id="myForm">   <div>    <div>     <div class="inputs">      <input id="username" type="text" name="username" placeholder="用户名"          required>      <input id="password" type="password" name="password" placeholder="密码"          required>     </div>     <div>      <input type="button" id="submit" onclick="getForm22(this)"          value="登录">     </div>    </div>   </div>  </form> </div> </body> </html>

注意 :参数是普通的html元素,返回的是jquery对象

(2)js把毫秒转化为时间

var releaseDate=new Date(Number(obj.releaseTime)*1000).format('MM-dd  HH:mm');//把毫秒数转化为日期

注意 :上述代码中 obj.releaseTime的单位是秒(不是毫秒)

(3)把数组拼接为字符串:使用join

var html = [];         if(data.length2>0){             var recordList=data.recordList;             for(var i=0;i<data.length2;i++){                 html.push(getBBSCommentListItem(recordList[i]));             }             $livespanel_ul.append(html.join(''));         }

(4)web app中使用jsonp跨域请求时如何带上sessionid

跨域访问

在url地址最后面加上 ;jsessionid= <你的实际sessionid>

实例

var modi_url='http://'+server_url+'/user/mod_pass?callback=?&password='+old_password_val+"&password2="+new_password_val+";jsessionid="+window.sessionId; console.log&&console.log(modi_url); $.jsonP({url:modi_url,success:function(data){  var result=data.result;  hideMask2();  switch (result)  {   case 1:    user.password=new_password_val;    alert("修改成功");    $.ui.goBack();    break;   case 23:    alert("新密码不能为空");    break;   case 21:    alert("请先登录");    $.ui.goBack();    break;   case 22:    alert("两次密码不能相同");    break;   case 24:    alert("密码已过期,请点击右上角的刷新按钮");    break;  } }});

(5)创建数组

var html = [];

(6)判断对象是否包含指定属性

'length' in objArr 可以判断 objArr 是否包含length属性

示例:

if (!('length' in objArr)) {// just only single component (not array).  objArr.style.display = "block";     }else{  for ( var i = 0; i < objArr.length; i++) {   var objOne = objArr[i];   objOne.style.display = "block";  }     }

(7)获取浏览器类型

jquery-1.11.1.js中没有了获取浏览器的方法,可以添加如下代码

/***  * get browser type  * @param jQuery  */ var checkBrowser = function (jQuery) {  if (jQuery.browser) return;  jQuery.browser = {};  jQuery.browser.mozilla = false;  jQuery.browser.webkit = false;  jQuery.browser.opera = false;  jQuery.browser.msie = false;  var nAgt = navigator.userAgent;  jQuery.browser.name = navigator.appName;  jQuery.browser.fullVersion = '' + parseFloat(navigator.appVersion);  jQuery.browser.majorVersion = parseInt(navigator.appVersion, 10);  var nameOffset, verOffset, ix; // In Opera, the true version is after "Opera" or after "Version"  if ((verOffset = nAgt.indexOf("Opera")) != -1) {   jQuery.browser.opera = true;   jQuery.browser.name = "Opera";   jQuery.browser.fullVersion = nAgt.substring(verOffset + 6);   if ((verOffset = nAgt.indexOf("Version")) != -1)    jQuery.browser.fullVersion = nAgt.substring(verOffset + 8);  } // In MSIE, the true version is after "MSIE" in userAgent  else if ((verOffset = nAgt.indexOf("MSIE")) != -1) {   jQuery.browser.msie = true;   jQuery.browser.name = "Microsoft Internet Explorer";   jQuery.browser.fullVersion = nAgt.substring(verOffset + 5);  } // In Chrome, the true version is after "Chrome"  else if ((verOffset = nAgt.indexOf("Chrome")) != -1) {   jQuery.browser.webkit = true;   jQuery.browser.name = "Chrome";   jQuery.browser.fullVersion = nAgt.substring(verOffset + 7);  } // In Safari, the true version is after "Safari" or after "Version"  else if ((verOffset = nAgt.indexOf("Safari")) != -1) {   jQuery.browser.webkit = true;   jQuery.browser.name = "Safari";   jQuery.browser.fullVersion = nAgt.substring(verOffset + 7);   if ((verOffset = nAgt.indexOf("Version")) != -1)    jQuery.browser.fullVersion = nAgt.substring(verOffset + 8);  } // In Firefox, the true version is after "Firefox"  else if ((verOffset = nAgt.indexOf("Firefox")) != -1) {   jQuery.browser.mozilla = true;   jQuery.browser.name = "Firefox";   jQuery.browser.fullVersion = nAgt.substring(verOffset + 8);  } // In most other browsers, "name/version" is at the end of userAgent  else if ((nameOffset = nAgt.lastIndexOf(' ') + 1) <   (verOffset = nAgt.lastIndexOf('/'))) {   jQuery.browser.name = nAgt.substring(nameOffset, verOffset);   jQuery.browser.fullVersion = nAgt.substring(verOffset + 1);   if (jQuery.browser.name.toLowerCase() == jQuery.browser.name.toUpperCase()) {    jQuery.browser.name = navigator.appName;   }  } // trim the fullVersion string at semicolon/space if present  if ((ix = jQuery.browser.fullVersion.indexOf(";")) != -1)   jQuery.browser.fullVersion = jQuery.browser.fullVersion.substring(0, ix);  if ((ix = jQuery.browser.fullVersion.indexOf(" ")) != -1)   jQuery.browser.fullVersion = jQuery.browser.fullVersion.substring(0, ix);  jQuery.browser.majorVersion = parseInt('' + jQuery.browser.fullVersion, 10);  if (isNaN(jQuery.browser.majorVersion)) {   jQuery.browser.fullVersion = '' + parseFloat(navigator.appVersion);   jQuery.browser.majorVersion = parseInt(navigator.appVersion, 10);  }  jQuery.browser.version = jQuery.browser.majorVersion; }; checkBrowser(jQuery);

以上用于jquery .

下面的不是用于jquery的 :

/***  * get browser type and browser version and language  when page open,the function will be executed automaticly  * @param write22  * @returns {{systemLanguage,userLanguage,ver}}  */ com.whuang.hsj.getBrowserVersion=(function(write22){  var browser = {}; // console.dir(navigator);  var userAgent = navigator.userAgent.toLowerCase();  /*for(osvId in navigator){   var value222=navigator[osvId];   document.writeln(osvId+": "+value222+'<br>');  }*/  var lang22=navigator.language; // document.writeln(userAgent+'<br>'); // document.writeln(navigator.appCodeName+'<br>');  var s;  (s = userAgent.match(/msie ([/d.]+)/)) ? browser.ie = s[1] : (s = userAgent.match(/firefox//([/d.]+)/)) ? browser.firefox = s[1] : (s = userAgent.match(/chrome//([/d.]+)/)) ? browser.chrome = s[1] :   (s = userAgent.match(/opera.([/d.]+)/)) ? browser.opera = s[1] : (s = userAgent.match(/version//([/d.]+).*safari/)) ? browser.safari = s[1] : 0;  var version = "";  if (browser.ie) {   version =  browser.ie;   if(write22 && write22!=false && write22!='false'){    document.writeln('IE<br>');   }   if(!browser.lang ||browser.lang==undefined){    lang22=navigator.browserLanguage;    browser.systemLanguage=navigator.systemLanguage ;    browser.userLanguage=navigator.userLanguage;   }  }  else  if (browser.firefox) {   version = browser.firefox;   browser.mozilla=browser.firefox;   if(write22 && write22!=false && write22!='false'){    document.writeln('firefox<br>');   }  }  else  if (browser.chrome) {   version = browser.chrome;   if(write22 && write22!=false && write22!='false'){    document.writeln('chrome<br>');   }  }  else  if (browser.opera) {   version =  browser.opera;   if(write22 && write22!=false && write22!='false'){    document.writeln('opera<br>');   }  }  else  if (browser.safari) {   version =  browser.safari;   if(write22 && write22!=false && write22!='false'){    document.writeln('Safari<br>');   }  }  else {   version = 'unknown browser';  }  browser.ver=version;  if(lang22 && lang22!=undefined)  {   browser.lang=lang22.toLowerCase();  }  return browser; })();

使用方法:

var brow ;   if(com.whuang.hsj.getBrowserVersion){    brow =com.whuang.hsj.getBrowserVersion;   }   if(type22=='mid'||type22=='middle'){    $("#loadPanel").css("background-image", "url(/"../static/images/loading/loading_middle.gif/")");    if(brow&&brow.chrome){//因为在chrome 中有时背景图片gif不显示     $("#loading_gif").css("display","block");    $("#loading_gif").attr("src", "../static/images/loading/loading_middle.gif");     }       }else if(type22=='small'||type22=='little'){    $("#loadPanel").css("background-image", "url(/"../static/images/loading/loading_small.gif/")");    if(brow&&brow.chrome){//因为在chrome 中有时背景图片gif不显示     $("#loading_gif").css("display","block");    $("#loading_gif").attr("src", "../static/images/loading/loading_small.gif");   }   }else{    $("#loadPanel").css("background-image", "url(/""+type22+"/")");   }

(8)通过name属性获取单个元素

/***  * if is radio ,please use com.whuang.hsj.$$arr  * @param name22  * @returns  */ com.whuang.hsj.$$one = function(name22) {  if (com.whuang.hsj.isHasValue(name22)) {   var names222=document.getElementsByName(name22);   //alert("names222:"+names222);   //alert("typeof:"+(typeof names222 ));   var className=Object.prototype.toString.call(names222);   var boolean_isArray;   var ieHtmlCollection='[object HTMLCollection]';   if(isIEtest)//if browser is IE   {                  boolean_isArray=( className=== '[object Object]') ||(className=== ieHtmlCollection) ||names222 instanceof Array ;   }else   {                  boolean_isArray=( className=== '[object Array]') ||(className=== '[object NodeList]'  )||(className==ieHtmlCollection)||names222 instanceof Array||names222 instanceof NodeList;   }   if(names222){              if(boolean_isArray){                      return names222[0];              }else{                      return names222;    }   }else{    return "";   }  } else {   return "";  } };

使用场景:

html代码:

<input id="username" type="text" name="username" placeholder="用户名"                            required>

js代码

var username=com.whuang.hsj.$$one("username");         alert(username.value);

(9)字符串 source 中是否包含 key2

com.whuang.hsj.contains=function(source,key2){  var isDownload=(source.indexOf(key2)>-1);  if(isDownload){   return true;  }else{   return false;  } }

(10)判断以指定字符串开头或结尾

com.whuang.hsj.startWith=function(str,regex){  if(regex==undefined||str==undefined){  return false;     }  return str.indexOf(regex)==0; }; com.whuang.hsj.endWith=function(str,regex){  return str.lastIndexOf(regex)==str.length-regex.length; };

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