JavaScript interview questions from qq_javascript skills

Copy code The code is as follows:

var info="Tencent Paipai.com (www.paipai.com) It is a well-known e-commerce website owned by Tencent. ";
info ="Paipai.com was launched on September 12, 2005.";
info ="It was officially launched on March 13, 2006.";
info ="It is currently the second largest e-commerce platform in China.";
info=info.split(",");
for(var i=0; i{
alert(info[i]);
}

This question seems like a toss-up at first, because later you have to separate each item with a comma and then alert each item. Why not construct an array? Object to store text content, and a temporary variable info is used to store
such as var info=["Tencent Paipai.com (www.paipai.com) is a well-known e-commerce website under Tencent.","Paipai.com in It was launched online on September 12, 2005, and officially launched on March 13, 2006. It is currently the second largest e-commerce platform in China. But then I thought that if it was optimization, this question would be meaningless.
Look carefully at the info variable and find that it adds a string every time. If the string is large and numerous, it will greatly affect the performance.

The string type in js is a basic type, so generally they are stored on the stack. If the string is large, info will become a very long string each time, which will be very slow

It would be much better if it is stored in a reference type array, such as

Copy code The code is as follows:

var temp=[];
temp.push("Tencent Paipai (www.paipai) .com) is a well-known e-commerce website owned by Tencent. ");
temp.push()....//temp is just a pointer to an array on the heap
....

The last trick is temp.join(""). This idea can be adopted for dealing with large string connection problems.