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What does attr mean in javascript

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Release： 2022-02-08 11:14:29

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In JavaScript, attr is an attribute operation method, which can set or return the attribute value of the selected element. The syntax is "$(selector).attr(attribute)" or "$(selector) .attr(attribute,value)”.

What does attr mean in javascript

The operating environment of this tutorial: Windows 10 system, JavaScript version 1.8.5, Dell G3 computer.

What does attr mean in javascript

attr() method sets or returns the attribute value of the selected element.

Returns the attribute value of the selected element.

Syntax

$(selector).attr(attribute)

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attribute specifies the attribute whose value is to be obtained.

Set the attributes and values of the selected element.

Syntax

$(selector).attr(attribute,value)

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attribute specifies the name of the attribute.

value Specifies the value of the attribute.

Set the attributes and values of the selected element.

$(selector).attr(attribute,function(index,oldvalue))

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attribute specifies the name of the attribute.

function(index,oldvalue) specifies the function that returns the attribute value.

This function can receive and use the index value of the selector and the current attribute value.

Set more than one attribute and value for the selected element.

Syntax

$(selector).attr({attribute:value, attribute:value ...})

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attribute:value Specifies one or more attribute/value pairs.

The example is as follows:

<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
  $("button").click(function(){
    $("img").attr("width",function(n,v){
      return v-50;
    });
  });
});
</script>
</head>
<body>
<img  src="/i/eg_smile.gif"    style="max-width:90%"  style="max-width:90%" / alt="What does attr mean in javascript" >
<br />
<button>减少图像的宽度 50 像素</button>
</body>
</html>

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Output result:

What does attr mean in javascript

After clicking the button:

What does attr mean in javascript

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