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javascript built-in objects (partial content)
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- 2018-08-09 15:32:021608browse
text object
The Text object represents a text input field in an HTML form. Each time input type="text appears in an HTML form, a Text object will be created.
disabled Sets or returns whether the text field should be disabled. (There are only two values: true and false)
readOnly Sets or returns Whether the text field should be read-only (can only be read, cannot be modified). (There are only two values: true and false)
value sets or returns the value of the value attribute of the text field.
focus() in Set focus on the text field.
eg:
<form>
<input name="wd" />
<input type="button" onclick="onesubmit()" value= "搜索" />
</form>
<script>
var form = document.getElementsByTagName("form")[0];
form.action = "https://www.baidu.com/s"; var text = document.getElementsByName("wd")[0]; function onesubmit(){
text.value = "中国";//设置或返回文本域的 value 属性的值
console.log(text.value);
text.focus();//在文本域上设置默认焦点
text.readOnly = true;//设置或返回文本域是否应是只读的 即不能更改
text.disabled = true;//设置或返回文本域是否应被禁用,即不能使用
} </script>radio object
Radio object represents the radio button in the HTML form.
checked Sets or returns the radio button The state. (true and false)
disabled Sets or returns whether the radio button is disabled.
value Sets or returns the value of the value attribute of the radio button.
checkbox object
Checkbox object represents a check box in an HTML form.
checked sets or returns the state of a multi-select button.
disabled sets or returns whether a button should be disabled.
value sets or Returns the value of the value attribute of the checkbox.
eg:
<body>
<form onsubmit="return check()">
用户名<input name="user_name" id="user_name" /><br />
密码<input name="password" id="password" type="password" /><br />
确认密码<input name="pw_check" id="pw_check" type="password" /><br />
<input type="reset" value="重置" />
<input type="submit" value="注册" />
<input type="radio" name="sex" value="男" />男 <input type="radio" name="sex" value="女" />女 <input type="checkbox" name="hobby" value="篮球" />篮球 <input type="checkbox" name="hobby" value="羽毛球" />羽毛球 <input type="checkbox" name="hobby" value="乒乓球" />乒乓球 <input type="checkbox" name="hobby" value="足球" />足球 <select name="choose" id="choose">
<option value="gaoyi">高一</option>
<option value="gaoer">高二</option>
<option value="gaosan">高三</option>
</select>
</form>
<span id="msg" style="color: red;"></span>
<script>
function $(id){
return document.getElementById(id);
} function check(){
var selects = document.getElementById("choose");
selects.disabled=true;
console.log(selects.length);
console.log(selects.selectedIndex); var options = selects.options; for(var i=0;i<options.length;i++){
console.log(options[i].value)
}
console.log("$$$$$$$$$$$$$$$$$$$$$$$$$$$$"); var radios = document.getElementsByName("sex"); for(var i=0;i<radios.length;i++){
console.log(radios[i].checked+radios[i].value);
}
radios[0].cheked=true;
radios[0].disabled=true;
console.log("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"); var checkboxes = document.getElementsByName("hobby"); for(var i=0;i<checkboxes.length;i++){
console.log(checkboxes[i].checked+checkboxes[i].value)
}
checkboxes[2].checked=true;
checkboxes[2].disabled=true;
console.log("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"); var user_name = $("user_name").value; var password = $("password").value; var pw_check = $("pw_check").value; if(user_name.length==0){
$("msg").innerHTML = "用户名不能为空"; return false;
} else if(user_name.length>12){
$("msg").innerHTML = "用户名不能超过12个字符"; return false;
} if(password.length==0){
$("msg").innerHTML = "密码不能为空"
return false;
} else if(password.length>15){
$("msg").innerHTML = "密码不能超过12个字符"; return false;
} if(password!=pw_check){
$("msg").innerHTML = "密码不一致"; return false;
}
console.log("注册成功") return false;
} </script>
</body>Select object
The Select object represents a drop-down list in an HTML form.
options[ ] Returns an array containing all options in the drop-down list.
disabled Sets or returns whether the drop-down list should be disabled.
length Returns the number of options in the drop-down list.
selectedIndex Sets or returns the selected option in the drop-down list Destination index number. (Start from 0)
add() Add an option to the drop-down list.
remove() Remove an option from the drop-down list.
option object
Option(text,value) Creates an Option object through text (that is, the value between option tags) and value value
selected Sets or returns the value of the selected attribute. (true or false, that is, whether it is selected)
text Sets or Returns the plain text value of an option.
value Sets or returns the value sent to the server.
eg:
<html>
<head>
<meta charset="utf-8" />
<title></title>
</head>
<body>
<select id="selected">
<option value="小学一年级">一年级</option>
<option value="小学二年级">二年级</option>
<option value="小学三年级">三年级</option>
<option value="小学四年级">四年级</option>
<option value="小学五年级">五年级</option>
<option value="小学六年级">六年级</option>
</select>
<input type="button" onclick="test()" value="按钮" />
<script>
function test(){
var selects = document.getElementById("selected");
console.log(selects.disabled);
console.log(selects.selectedIndex);
console.log(selects.length);
console.log("@@@@@@@@@@@@@@@@@@@@@@@@"); var options = selects.options;
console.log(options[selects.selectedIndex]);
console.log("$$$$$$$$$$$$$$$$$"); for (var i=0;i<options.length;i++){
console.log(options[i].value);
console.log(options[i].selected);
console.log(options[i].text);
}
console.log("######################"); var option1 = new Option("初一","初中一年级"); var option2 = new Option("初二","初中二年级"); var option3 = new Option("初三","初中三年级");
selects.add(option2);
selects.add(option1);
selects.remove(6);
selects.add(option2);
selects.add(option3);
selects.remove(0);
selects.remove(0);
selects.remove(0);
selects.remove(0);
selects.remove(0);
selects.remove(0);
} </script>
</body></html>element object
In the HTML DOM, the Element object Represents an HTML element. This object can have child nodes of type element node, text node, and comment node. Obtain the Element object through the getElementById() method, getElementsByTagName() or getElementsByName() method of the Document object.
element.className Sets or returns the class attribute of the element.
element.innerHTML Sets or returns the content of the element.
element.style Sets or returns the style attribute of the element.
element.parentNode returns the parent node of the element as a Node object.
eg:
<head>
<meta charset="utf-8" />
<title></title>
</head>
<script>
function news(){
var elements1 = document.getElementById("news");
elements1.className = "selected"; var elements2 = document.getElementById("see");
elements2.className = "fault"; var elements3 = document.getElementById("list1");
elements3.className = "visited"; var elements3 = document.getElementById("list2");
elements3.className = "unvisited";
} function see(){
var elements = document.getElementById("news");
elements.className = "fault";
var elements2 = document.getElementById("see");
elements2.className = "selected"; var elements3 = document.getElementById("list1");
elements3.className = "unvisited"; var elements3 = document.getElementById("list2");
elements3.className = "visited";
} </script>
<style>
body { color: #333; padding: 5px 0; font: 12px/20px "SimSun","宋体","Arial Narrow",HELVETICA; background: #fff; }
a{ color: #666; text-decoration: none; }
a:visited{ color:#666; }
p{ display: block; }
#main{ position: relative; display: block; height: 34px; width: 356px; border: 1px solid #dbdee1; line-height: 34px; background: url(img/bg1px.png) 0 -33px repeat-x; zoom: 1; /*缩放比例*/
}
#main:after{ content: "."; display: block; height: 0; clear: both; visibility: hidden;/*隐藏h2标签*/
}
#main #menu{ float: left; margin-left: -2px; }
#main #menu span{ float: left; height: 35px; line-height: 35px; font-size: 16px; font-family: "Microsoft YaHei","微软雅黑","SimHei","黑体"; padding: 0 13px; margin-top: -1px; }
#main #menu .selected{ height: 33px; line-height: 29px; border-top: 3px solid #ff8400; border-left: 1px solid #dbdee1; border-right: 1px solid #dbdee1; background-color: #fff; _position: relative; _margin-bottom: -1px; padding: 0 12px; border-left: 0; padding-left:13px ; }
#main #date{ float: right; display: inline; margin-right: 10px; }
#list1{ position: absolute; }
#list2{ position: absolute; }
#list1 a{ color: #122e67; text-decoration: none; }
#list1 a:visited{ color: #52687e; text-decoration: none; }
#list2 a{ color: #122e67; text-decoration: none; }
#list2 a:visited{ color: #52687e; text-decoration: none; }
.visited{ display: block; }
.unvisited{ display: none; }
ul{ height: auto; height: 208px; overflow: hidden; clear: both; list-style: none; display: block; }
ul li{ padding-left: 10px; line-height: 26px; height: 26px; overflow: hidden; font-size: 14px; background: url(//i0.sinaimg.cn/home/main/index2013/0403/icon.png) no-repeat 0 -881px; _zoom: 1; }
</style>
<body>
<p id="main">
<p id="menu">
<span id="news" class="selected" onmouseover="news()">
<a href="http://news.sina.com.cn/" target="_blank">新闻</a>
</span>
<span id="see" class="fault" onmouseover="see()">
<a href="http://henan.sina.com.cn/" target="_blank">看河南</a>
</span>
</p>
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</p>
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</body>The above example is to imitate the effect of switching labels and displaying content by moving the mouse on the Sina page.
window object
In fact, commonly used history, document and other objects belong to the window object, but the window object is a global variable, and "window." is generally omitted in use.
document object
domain returns the domain name of the current document, for example: www.blue-bridge.com
URL returns the URL of the current document, for example: http://www.blue- bridge.com/venus/login.jsp
getElementById() Returns a reference to the first object with the specified id.
getElementsByName() Returns a collection of objects with the specified name.
getElementsByTagName() returns a collection of objects with the specified tag name.
history object
back() loads the previous URL in the history list, the same as the "back" button.
forward() loads the next URL in the history list, the same as the "forward" button.
go() loads a specific page in the history list, history.go(-1)//is equivalent to back().
Related recommendations:
Application example of TextRange object for processing part of text
Single built-in object of "JavaScript Breakthrough"
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