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Xiaoqiang's HTML5 mobile development road (32) - JavaScript review 7

黄舟

Feb 04, 2017 pm 02:35 PM

BOM model browser object model (browser object model), the browser itself can be operated through some objects built into the browser.
DOM is used to operate the page, and BOM is used to operate the browser itself.

BOM is not standardized, but most browsers support the following objects

1. Window object: represents the entire window

(1) open Method: (name, characteristics, height and width, toolbar, scroll bar)

(2) setTimeout method: setTimeout(fn, milliseconds); //The first parameter must be a function name (no brackets allowed) )

<html>  
    <head>  
        <script>  
            function f1(){  
            //win指向了新打开的窗口   
                    var win = window.open(&#39;day05_03&#39;,&#39;wi_1&#39;,  
                    &#39;width=400,height=400&#39;);  
                    setTimeout(function(){  
                    win.close();  
                }, 5000);         
            }  
        </script>  
    </head>  
    <body>  
        <input type="button" value="click me" onclick="f1();"/>  
    </body>  
</html>

(3) setInterval method

var taskId = setInterval(fn, milliseconds); //Execute a function after the specified time interval

(4) clearInterval method

clearInterval(taskId); //Cancel the task of setInterval

<html>  
    <head>  
        <style>  
            #d1{  
                width:80px;  
                height:80px;  
                background-color:blue;  
                position:relative;  
            }  
        </style>  
        <script src="myjs.js"></script>  
        <script>  
            function f2(){  
                var v1 = parseInt($(&#39;d1&#39;).style.left);  
                $(&#39;d1&#39;).style.left = v1 + 50 + &#39;px&#39;;  
            }  
            function f1(){  
                var taskId = setInterval(f2, 500);  
                setTimeout(function(){  
                    clearInterval(taskId);  
                },5000)  
            }  
        </script>  
    </head>  
    <body>  
        <div id="d1" style="left:10px;"></div>  
        <input type="button" value="click me"  
        onclick="f1();"/>  
    </body>  
</html>

(5) alert() method Pop up a warning dialog box

(6) confirm() method

var flag = confirm(string); //string is the prompt message, flag returns true or false

(7) prompt method

var info = prompt(string)

<html>  
    <head>  
        <script>  
            function f3(){  
                var flag = confirm(&#39;你喜欢钱吗？&#39;);  
                alert(flag);  
            }  
            function f4(){  
                var info = prompt(&#39;请输入手机号&#39;);  
                alert(&#39;你输入的手机号是：&#39; + info);  
            }  
        </script>  
    </head>  
    <body>  
        <input type="button" value="click me"  
        onclick="f4();"/>  
    </body>  
</html>

2. Document object: represents the root of the entire document

getElementById(id);
createElement(tagName);

write(string); Output relevant information at the specified location

<html>  
    <!-- document对象 -->  
    <head></head>  
    <body style="font-size:30px;">  
        开始输出helloword<br/>  
        <script>  
            for(i=0; i<100; i++){  
                document.write(&#39;hello world<br/>&#39;);  
            }  
        </script>  
    </body>  
</html>

3, Location object: encapsulated Related information of the browser address bar
href attribute: Specify the page to be loaded
reload method: Reload the current page, which is equivalent to refreshing

<html>  
    <!-- location对象 -->  
    <head></head>  
    <body>  
        <input type="button"   
        value="跳转到另外一个页面" onclick="location.href = &#39;day05_04.html&#39;;"/><br/>  
        <input type="button"  
        value="刷新当前页面" onclick="location.reload();"/>  
    </body>  
</html>

4, History object: Encapsulates the browser has visited Related information about the past page
back(): go back
forward(): go forward
go (parameter): positive number goes forward, negative number goes back

<html>  
    <!-- history对象    -->  
    <head></head>  
    <body>  
        <input type="button"  
        value="点这里后退" onclick="history.back();"/>  
        <input type="button"  
        value="点这里前进" onclick="history.forward();"/>  
        <input type="button"  
        value="点这儿后退"  onclick="history.go(-1);"/>  
    </body>  
</html>

5, Navigator object : Encapsulates the relevant information of the browser, (such as: type, version)

<html>  
    <!--navigator对象-->  
    <head></head>  
    <body>  
        现在访问的浏览器的相关信息如下：<br/>  
        <script>  
        var info;  
        //for in循环：主要用于遍历对象   
            for(propName in navigator){  //propName是任意变量  
        // 将navigator对象的属性名保存到propName变量里  
                info += propName + &#39;;&#39; +navigator[propName] + &#39;<br/>&#39;;  
            }  
            document.write(info);  //在当前页面输出  
        </script>  
    </body>  
</html>

<html>  
    <!--检测浏览器类型-->  
    <head>  
        <script>  
            function f1(){  
                if((navigator.userAgent).indexOf(&#39;Firefox&#39;)>0){  
                    alert("当前浏览器是Firefox");  
                }else if(navigator.userAgent.indexOf(&#39;MSIE&#39;)>0){  
                    alert("当前浏览器是IE");  
                }else{  
                    alert("其他浏览器");  
                }  
            }     
        </script>  
    </head>  
    <body>  
        <input type="button"  
        value="获得当前浏览器的类型" onclick="f1();"/>  
    </body>  
</html>

6, Screen object: the relevant information of the screen where the browser is located

<html>  
    <head>  
        <script>  
            function f2(){  
                alert(screen.width + &#39; &#39; +  
                screen.height);  
            }     
        </script>  
    </head>  
    <body>  
        <input type="button"  
        value="获得screen相关信息" onclick="f2();"/>  
    </body>  
</html>

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