How to connect strings in js

JS method of connecting strings: 1. Use the string concatenation operator " " to connect strings; 2. Use the concat() method of strings to connect strings; 3. Use the join() method of arrays connection string.

The operating environment of this article: Windows 7 system, Dell G3 computer, javascript version 1.8.5.

JS methods for connecting strings include: using the string concatenation operator " ", using the concat() method, and using the join() method.

In JavaScript, we can connect two or more strings to form a new string. This article will introduce you to the method of connecting strings in js, so that you can have some knowledge about string connections. I have a certain understanding, I hope it will be helpful to you.

String concatenation operator " "

" " " operator can be used to add strings to connect two or more string variables.

Example:

<div class="demo ">
	<p>str1="What a very"</p>
	<p>str2="nice day"</p>
	<p id="str3"></p>
</div>

<script type="text/javascript">
var str1="What a very";
var str2="nice day";
var str3= str1+" "+str2;
document.getElementById("str3").innerHTML ="str3=&#39;"+str3+"&#39;";
</script>

Rendering:

In the above example, the strings str1 and str2 are changed through the " " operator There is also an empty string concatenated to form a new string str3.

Concat() method of string

The concat() method is used to concatenate two or more strings or arrays and then return A new string or array.

Syntax:

string1. concat([string2[, string3[, . . . [, stringN]]]])

string1: Specify a String object or string carrier, and all other specified strings can be connected to this carrier; required.

string2,. . ., stringN: The optional parameter (one or more) in the concat() method is a string appended to the end of the string1 carrier.

Note:

1. If the specified string1 carrier is different and the parameters in the concat() method are different, the new string formed will also be different.

2. If there are parameters that are not strings in the concat() method, they will be converted into strings first and then connected to the end of string1.

Example: concat() method to connect string

<div class="demo ">
	<p>str1="12q"</p>
	<p>str2="12w"</p>
	<p>str3="111"</p>
	<p id="str4"></p>
	<p id="str5"></p>
	<p id="str6"></p>
</div>

<script type="text/javascript">
var str1=&#39;12q&#39;;
var str2="12w";
var str3="111";

var str4=str1.concat(str2,str3);
var str5=str2.concat(str1,str3);
var str6=str3.concat(str1,str2);

document.getElementById("str4").innerHTML ="str4=str1+str2+str3=&#39;"+str4+"&#39;";
document.getElementById("str5").innerHTML ="str5=str2+str1+str3=&#39;"+str5+"&#39;";
document.getElementById("str6").innerHTML ="str6=str3+str1+str2=&#39;"+str6+"&#39;";
</script>

Rendering:

array The join() method

join() method is used to put all the elements in the array into a string. The elements in the array will be separated by the specified delimiter.

Syntax:

arrayObject.join(separator);

separator parameter: used to specify the separator style to be used, which can be omitted; if omitted, a comma is used as the separator.

Example: join() method to connect strings

<div class="demo ">
	<p>arr[0]="www"</p>
	<p>arr[1]=="php"</p>
	<p>arr[2]=="cn"</p>
	<p id="str1"></p>
	<p id="str2"></p>
	<p id="str3"></p>

</div>

<script type="text/javascript">
var arr=new Array();
arr=["www","php","cn"];
var str1=arr.join(".");
var str2=arr.join("-");
var str3=arr.join(" ");
document.getElementById("str1").innerHTML ="str1=&#39;"+str1+"&#39;";
document.getElementById("str2").innerHTML ="str2=&#39;"+str2+"&#39;";
document.getElementById("str3").innerHTML ="str3=&#39;"+str3+"&#39;";
</script>

Rendering:

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