Community Learn Tools Library Leisure
search
English
Home > Web Front-end > JS Tutorial > Application of eval() function and trim() in js to remove left and right spaces from string_javascript skills

Application of eval() function and trim() in js to remove left and right spaces from string_javascript skills

WBOY
Release： 2016-05-16 17:42:26
Original
1574 people have browsed it

Understand the eval() function in js and write a function trim() to remove the left and right spaces in the string.
trim() refers to the source code of jquery, you can use it with confidence.

My understanding of the eval() function in js is not necessarily correct.

Copy code The code is as follows:







There is no trim function in js to handle spaces before and after string filtering,

and jquery This very commonly used function has been added, and its source code is as follows

function trim(t){

return (t||"").replace(/^s |s $/ g, "");

}

Sometimes we don’t use jquery, there is no need to add the entire jquery library for a function,

At this time we can copy the source code Just write a trim function.



<script> <br>var f='hello'; <br>//alert(f); <br> /* <br>By the way, here is the eval() function, which can calculate the content in the brackets as a js script. <br> It can also calculate mathematical operations and string calculations. <br>In short, it is not a simple string concatenation function. <br>You can think of it as a js script in js. <br>This is very similar to jsp. JSP is the java code embedded in html. <br>The content in the eval() brackets is the js code embedded in js. <br>*/ <br>//eval("alert('" f "')");//Calculate the js script, which has the same effect as alert(f). <br>eval(" var gg='haha'"); <br>alert(eval("gg"));//The content in eval is the embedded js code, which is equivalent to var gg='haha', alert (gg); <br>//alert(eval('3 4'));//Calculate mathematical operations, the result is 7 <br>//alert(eval('3' '4'));//Calculate characters String, result 34 <br>alert("start" trim(' abc def ') "end"); <br>//The trim function in jquery filters out the first space. <br>function trim(t){ <br>return (t||"").replace(/^s |s $/g, ""); <br>} <br></script>
Related labels：
eval trim
source：php.cn
Previous article：Overview of submit() method and onsubmit event application of form elements_Basic knowledge Next article：Jquery UI vibration effect implementation principle and steps_jquery
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
function_exists() cannot determine the custom function Function test () {return true;} if (function_exists ('test')) {echo "test is function...
From 2024-04-29 11:01:01
0
3
2041
How to display the mobile version of Google Chrome Hello teacher, how can I change Google Chrome into a mobile version?
From 2024-04-23 00:22:19
0
11
2200
The child window operates the parent window, but the output does not respond. The first two sentences are executable, but the last sentence cannot be implemented.
From 2024-04-19 15:37:47
0
1
1855
There is no output in the parent window document.onclick = function(){ window.opener.document.write('I am the output of the child ...
From 2024-04-18 23:52:34
0
1
1745
Where is the courseware about CSS mind mapping? Courseware
From 2024-04-16 10:10:18
0
0
1766
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template