Learn to punch in today

jQuery

1. Learned two ways of traversal

// The first main traversal dom object 
    $('div').each(function (index, domEle) {
    
        console.log(index);
        // The second parameter is dom object , First convert 
        console.log($(domEle));
    })
    // The second traversal method , It's mainly used to process data , You can traverse any object , Array etc. 
    $.each($('div'), function (i, element) {
    
        // The first parameter is the index , The second is the corresponding value , similar java Of foreach
    })

2. How to set and get properties
   about style In the properties of the ：
   Return property value
   $(“p”).css(“ Property name ”);
   Setting property values
   $(“p”).css(“ Property name ”,“ Property value ”);
   Set up multiple
   $(“p”).css({“background-color”:“yellow”,“font-size”:“200%”});
   For the attributes of the tag ：
   Returns the value of the property ：
   $(selector).prop(property)
   Set properties and values ：
   $(selector).prop(property,value)
   Use functions to set properties and values ：
   $(selector).prop(property,function(index,currentvalue))
   Set multiple properties and values ：
   $(selector).prop({property:value, property:value,…})
   Be careful
   prop() Method to set or return the properties and values of the selected element .
   When this method is used to return a property value , Then returns the value of the first matching element .
   When this method is used to set the property value , Set one or more attributes for the set of matching elements / It's worth it .
   Be careful ：prop() Method should be used to retrieve property values , for example DOM attribute （ Such as selectedIndex, tagName, nodeName, nodeType, ownerDocument, defaultChecked, and defaultSelected）.
   For custom properties
   Returns the value of the property ：
   $(selector).attr(attribute)
   Set properties and values ：
   $(selector).attr(attribute,value)
   Use functions to set properties and values ：
   $(selector).attr(attribute,function(index,currentvalue))
   Set multiple properties and values ：
   $(selector).attr({attribute:value, attribute:value,…})

prop and attr You can get the attribute value , but prop We don't scan the source code to get it, but according to the information of the page .

3. About new elements
   With jquery Way to create ：

  var txt2=$("<p></p>")

Or by html()
How to add elements ：
append() - In the selected element Inside Insert at the end of , Father and son
prepend() - In the selected element Inside Insert at the beginning of , Father and son
after() - In the selected element after Insert content , Brotherhood
before() - In the selected element Before Insert content , Brotherhood
Delete element mode ：
remove() - Delete selected elements （ And its subelements ）
empty() - Remove child elements from selected elements