Summary of some common methods of js_basic knowledge

Val(),append(),get(),split(),substr(),each(),html(),keyup(),trim(),show(),hide(),indexOf()
Look at it one by one:
Val(): to get and assign values ​​to a page element
Value: var result = $(“#txtSearch”).val();
Assignment :$("#txtSearch").val(result);

Each(): Operation on a collection, calling subsequent methods on each element in the collection, for example:
$. each(data.list, function (i, item) {
Alert(item["WikiTitle"]" ” item["WikiID"]);//i is the element of the collection in the following table, item represents the element itself
});

Append(): Append elements after the specified page element
For example, a list element

test!

, page elements like this can be appended Method to dynamically add multiple

items. For example:
There is a div with id="div_keycontent" in the page:

It can be done in Js Write like this:
$.each(data.list, function (i, item) {
$("#div_keycontent").append("

" item["WikiTitle"] " View" "

");
});

Get(): on the page Obtaining data asynchronously, this method is a form of asynchronous binding, which is explained in my previous article, so I won’t go into it here.

Spilt(): Operate on strings. For example:
Var str = spit(“liu,ming,feng”,”,”);
The str returned in this way is a string array : {"liu", "ming", "feng"}

Substr(); For string operations, remove the substrings inside
Usage:
///Judge the last one Whether the character is a comma
if (str.substring(str.length - 1, str.length) == "," || str.substring(str.length - 1, str.length) == ",") {
alert("The last character is a comma!");
}

Html(): Modify the content of an html tag, for example:
$("#div_keycontent") .html("

No data

");

Keyup(); Method triggered by keyboard press and popup
$("#txtSearchKey").keyup(function () {
$("#div_keycontent").html("

Data retrieval....

");
});

Trim( ): Remove the leading and trailing spaces of the string
Usage: str.trim();

Show(): Let the page elements be displayed. For example: $("#txtSearchKey").show();
Hide(): Hide elements of the page. For example: $("#txtSearchKey").hide();

Indexof(): Check whether there is a corresponding substring in the string
Usage:
if (str.indexOf(',,') != -1 || str.indexOf(',,') != -1) {///Determine whether there are consecutive commas
alert("There are two Use commas together! ”);
}