Restrict zero at the first character only in angular 2+. (expected output- 10101)












0














How to restrict zero at the first character only in the input field (expected output is like 10101)?



This is my way of doing.



HTML markup:



<input type="text" class="form-control col-md-4" #check (keypress)="isInteger($event)">


Typescript .ts file:



@ViewChild("check") inputFileld:ElementRef;

isInteger(event)
{
if(event.key=='0' && !this.inputFileld.nativeElement.value)
{
return false
}
}


With this trick, I'm not able to enter zero at first character but the problem is, write some number in the input field and select all the value and press zero that time zero is triggering.










share|improve this question
























  • Change the type to number and use pattern w3schools.com/tags/att_input_pattern.asp to limit the character via regex? Try that.
    – rrd
    Nov 22 at 18:47
















0














How to restrict zero at the first character only in the input field (expected output is like 10101)?



This is my way of doing.



HTML markup:



<input type="text" class="form-control col-md-4" #check (keypress)="isInteger($event)">


Typescript .ts file:



@ViewChild("check") inputFileld:ElementRef;

isInteger(event)
{
if(event.key=='0' && !this.inputFileld.nativeElement.value)
{
return false
}
}


With this trick, I'm not able to enter zero at first character but the problem is, write some number in the input field and select all the value and press zero that time zero is triggering.










share|improve this question
























  • Change the type to number and use pattern w3schools.com/tags/att_input_pattern.asp to limit the character via regex? Try that.
    – rrd
    Nov 22 at 18:47














0












0








0







How to restrict zero at the first character only in the input field (expected output is like 10101)?



This is my way of doing.



HTML markup:



<input type="text" class="form-control col-md-4" #check (keypress)="isInteger($event)">


Typescript .ts file:



@ViewChild("check") inputFileld:ElementRef;

isInteger(event)
{
if(event.key=='0' && !this.inputFileld.nativeElement.value)
{
return false
}
}


With this trick, I'm not able to enter zero at first character but the problem is, write some number in the input field and select all the value and press zero that time zero is triggering.










share|improve this question















How to restrict zero at the first character only in the input field (expected output is like 10101)?



This is my way of doing.



HTML markup:



<input type="text" class="form-control col-md-4" #check (keypress)="isInteger($event)">


Typescript .ts file:



@ViewChild("check") inputFileld:ElementRef;

isInteger(event)
{
if(event.key=='0' && !this.inputFileld.nativeElement.value)
{
return false
}
}


With this trick, I'm not able to enter zero at first character but the problem is, write some number in the input field and select all the value and press zero that time zero is triggering.







angular angular6 angular2-template






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edited Nov 22 at 19:09









marc_s

570k12811021250




570k12811021250










asked Nov 22 at 18:40









ranjan kumar rai

32




32












  • Change the type to number and use pattern w3schools.com/tags/att_input_pattern.asp to limit the character via regex? Try that.
    – rrd
    Nov 22 at 18:47


















  • Change the type to number and use pattern w3schools.com/tags/att_input_pattern.asp to limit the character via regex? Try that.
    – rrd
    Nov 22 at 18:47
















Change the type to number and use pattern w3schools.com/tags/att_input_pattern.asp to limit the character via regex? Try that.
– rrd
Nov 22 at 18:47




Change the type to number and use pattern w3schools.com/tags/att_input_pattern.asp to limit the character via regex? Try that.
– rrd
Nov 22 at 18:47












1 Answer
1






active

oldest

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0














HTML



<div>
<input type="text" class="form-control col-md-4" #check id="myText" (keypress)="isInteger($event)">
</div>


TS



isInteger(event) {

var ctl = document.getElementById('myText');
var startPos = ctl['selectionStart'];

if (startPos == 0 && String.fromCharCode(event.which) == '0') {
return false
}
}





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  • Thanks for the help.
    – ranjan kumar rai
    Nov 23 at 16:54











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1 Answer
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1






active

oldest

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oldest

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oldest

votes









0














HTML



<div>
<input type="text" class="form-control col-md-4" #check id="myText" (keypress)="isInteger($event)">
</div>


TS



isInteger(event) {

var ctl = document.getElementById('myText');
var startPos = ctl['selectionStart'];

if (startPos == 0 && String.fromCharCode(event.which) == '0') {
return false
}
}





share|improve this answer





















  • Thanks for the help.
    – ranjan kumar rai
    Nov 23 at 16:54
















0














HTML



<div>
<input type="text" class="form-control col-md-4" #check id="myText" (keypress)="isInteger($event)">
</div>


TS



isInteger(event) {

var ctl = document.getElementById('myText');
var startPos = ctl['selectionStart'];

if (startPos == 0 && String.fromCharCode(event.which) == '0') {
return false
}
}





share|improve this answer





















  • Thanks for the help.
    – ranjan kumar rai
    Nov 23 at 16:54














0












0








0






HTML



<div>
<input type="text" class="form-control col-md-4" #check id="myText" (keypress)="isInteger($event)">
</div>


TS



isInteger(event) {

var ctl = document.getElementById('myText');
var startPos = ctl['selectionStart'];

if (startPos == 0 && String.fromCharCode(event.which) == '0') {
return false
}
}





share|improve this answer












HTML



<div>
<input type="text" class="form-control col-md-4" #check id="myText" (keypress)="isInteger($event)">
</div>


TS



isInteger(event) {

var ctl = document.getElementById('myText');
var startPos = ctl['selectionStart'];

if (startPos == 0 && String.fromCharCode(event.which) == '0') {
return false
}
}






share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 22 at 23:20









Rak2018

540112




540112












  • Thanks for the help.
    – ranjan kumar rai
    Nov 23 at 16:54


















  • Thanks for the help.
    – ranjan kumar rai
    Nov 23 at 16:54
















Thanks for the help.
– ranjan kumar rai
Nov 23 at 16:54




Thanks for the help.
– ranjan kumar rai
Nov 23 at 16:54


















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