When working with text box input values in JavaScript, it is often used to "remove the front and back blanks" function. jquery's friends know that jquery provides a trim () function that can easily help us achieve this effect. However, if the project does not use a framework such as jquery, JS itself does not have such a function, we have to write their own functions, the following is the implementation of the function:
Copy CodeThe code is as follows:
For the user to invoke
function Trim (s) {
Return TrimRight (Trimleft (s));
}
Remove the left blank
function Trimleft (s) {
if (s = = null) {
Return "";
}
var whitespace = new String ("\t\n\r");
var str = new String (s);
if (Whitespace.indexof (Str.charat (0))! =-1) {
var j=0, i = str.length;
while (J < i && Whitespace.indexof (Str.charat (j))! =-1) {
j + +;
}
str = str.substring (j, I);
}
return str;
}
Remove the blank on the right
function TrimRight (s) {
if (s = = null) return "";
var whitespace = new String ("\t\n\r");
var str = new String (s);
if (Whitespace.indexof (Str.charat (str.length-1)) =-1) {
var i = str.length-1;
while (i >= 0 && whitespace.indexof (str.charat (i))! =-1) {
i--;
}
str = str.substring (0, i+1);
}
return str;
}
You only need to call the TRIM function when you use it.
The following is the implementation of the regular method:
Copy CodeThe code is as follows:
<script language= "JavaScript" >
<!--
String.prototype.Trim = function ()
{
Return This.replace (/(^\s*) | ( \s*$)/g, "");
}
String.prototype.LTrim = function ()
{
Return This.replace (/(^\s*)/g, "");
}
String.prototype.RTrim = function ()
{
Return This.replace (/(\s*$)/g, "");
}
-
</SCRIPT>
<input type= "text" value= "before and after" is a space "id=" space ">
<input type= "button" value= "go back and forth space" onclick= "javascript:document.getElementById (' space '). value= document.getElementById (' space '). Value. Trim ();d Ocument.getelementbyid (' Space '). Select (); " >
<input type= "button" value= "go to the front space" onclick= "javascript:document.getElementById (' space '). value= document.getElementById (' space '). Value. LTrim ();d Ocument.getelementbyid (' Space '). Select (); " >
<input type= "button" value= "go after the space" onclick= "javascript:document.getElementById (' space '). value= document.getElementById (' space '). Value. RTrim ();d Ocument.getelementbyid (' Space '). Select (); " >
<input type= "button" value= "Restore" onclick= "javascript:document.getElementById (' space '). Value= ' are spaces before and after"; >
JS trim function de-whitespace function and regular collection
