DOM 中对输入文本框的操作,光标靠近时候清楚文本框中内容,当光标移动开后,文本框中内容自动显示
1,( onfocus="Focus();" onblur="Blur();”)捕捉光标的两个js函数;
2. var tag = document.getElementById('i1'); 函数中获取根据id获取标签中内容;
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1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <div style="margin: 0 auto; 600px;background-color: blueviolet"> 9 <input id="i1" type="text" onfocus="Focus();" onblur="Blur();" value="请输入"/> 10 </div> 11 <script> 12 function Focus() { 13 // console.log(1); 14 var tag = document.getElementById('i1'); 15 var val = tag.value; 16 if (val == "请输入") { 17 tag.value = ''; 18 } 19 } 20 function Blur() { 21 // console.log(2); 22 var tag = document.getElementById('i1'); 23 var val = tag.value; 24 if (val.length == 0) { 25 tag.value = '请输入' 26 } 27 28 } 29 </script> 30 </body> 31 </html>
dom属性操作
console中对文本框中的style进行操作
obj=document.getElementById('i1');
<input id="i1" type="text" onfocus="Focus();" onblur="Blur();" value="请输入">
obj.setAttribute('name','fang');
undefined
obj=document.getElementById('i1');
<input id="i1" type="text" onfocus="Focus();" onblur="Blur();" value="请输入" name="fang">
obj.removeAttribute('name');
undefined
obj=document.getElementById('i1');
<input id="i1" type="text" onfocus="Focus();" onblur="Blur();" value="请输入">
属性操作
attributes
setAttribute
removeattribute
两种方法创建标签并添加到html
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1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <input type="button" value="+" onclick="AddText1();"> 9 <input type="button" value="+" onclick="AddText2();"> 10 <div id="i1"> 11 <!--//创建一个input标签在p标签内部包裹着--> 12 <p><input type="text"/></p> 13 </div> 14 15 <script> 16 //方法1:(字符串形式创建)直接创建一个被p标签包裹的input标签 加入到html中 17 function AddText1() { 18 var tag = "<p><input type='text'/></p>"; 19 document.getElementById('i1').insertAdjacentHTML("beforeEnd", tag); 20 } 21 22 //方法2:(以对象的方式)利用document创建一个input标签,为其添加style 23 // 创建一个p标签 24 // 将input标签加入到p标签中 25 function AddText2() { 26 var tag = document.createElement('input'); 27 //给input标签添加style 28 tag.setAttribute('type', 'text'); 29 // tag.style.fontSize='16px'; 30 var p = document.createElement('p'); 31 //创建一个p标签 32 p.appendChild(tag); 33 //将input标签加入到创建的p标签中 34 document.getElementById('i1').appendChild(p); 35 } 36 37 </script> 38 </body> 39 </html>
注意插入位置
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1 function AddText1() { 2 var tag = "<p><input type='text'/></p>"; 3 //第一个参数只能是'beforeBegin' 'afterBegin' 'beforeEnd' 'afterEnd' 4 // 代表插入标签的插入位置 5 document.getElementById('i1').insertAdjacentHTML("beforeEnd", tag); 6 }
任何标签都可以通过与js搭配提交表单
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1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <form id="i1" action="https://www.baidu.com"> 9 <input type="text"/> 10 <!--<input type="submit" value="提交"/>--> 11 <div style="background-color: #2459a2" onclick="submitForm();">div提交</div> 12 </form> 13 <script> 14 function submitForm() { 15 document.getElementById('i1').submit(); 16 } 17 </script> 18 </body> 19 </html>
setTimeout应用
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1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <div id="i1"></div> 9 <input type="button" value="删除" onclick="Del();"> 10 11 <script> 12 function Del() { 13 document.getElementById('i1').innerText = '已删除'; 14 setTimeout(function () { 15 document.getElementById('i1').innerText = ''; 16 }, 2000) 17 //2s后自动将标签中的文本自动删除,且只执行一次 18 } 19 </script> 20 </body> 21 </html>
终止定时器
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1 var timer1=setTimeout(function () {},5000); 2 clearTimeout(timer1); 3 4 var timer2=setInterval(function () {},5000); 5 clearInterval(timer2);
Dom事件的操作